How to prune plants

Cornus alba "Elegantissima"
Cornus alba “Elegantissima”

Pruning plants causes a lot of heart-ache amongst gardeners and a great deal is written about how it is done, often with little thought as to why it is done. It must always be remembered that all plants are either originally wild or descended from the wild  and nobody prunes plants in the wild. Before you start to prune a plant first ask yourself do you need to and if so why, what are you hoping to achieve. If in doubt, do nothing, if you do go ahead then be bold.

Reasons to prune:

  • Control size – often indicating the plant is in the wrong place.
  • Improve the flowering/fruiting – most fruit comes into this category, but many ornamental plants also respond to this.
  • Improved foliage – can apply to the shape, size, colouring or a combination of these.
  • Control disease – this can be preventative or to control a problem.

Reasons not to prune:

  • Make it look “tidy”
Hydrangea macrophylla cultivar
Hydrangea macrophylla cultivar

The basic rules.

Some things really apply to all pruning:

  1. Remove any dead or diseased branches – while trees can survive quiet happily with large amounts of dead and even rotted wood in there core; in most cases if the branch is dead or worse still diseased it need to be removed. Any shoot with  Coral Spot needs to be cut hard back as the disease will already have spread well into the living tissue below the characteristic red fruiting bodies.
  2. Remove crossing branches – these will end up rubbing against other ones, damage the bark and provide an entry point for disease. Also they crowd the centre of the plant, creating still air which favours pests and diseases.
  3. Make all cuts clearly and if back to a branching point don’t cut flush to the trunk, leave the swelling where the branch grows out of the main one.
  4. Don’t leave stubs – they look unsightly and are a entry point for disease.
  5. Bear in mind the larger the branch you cut off, the larger the wound and so the longer it will take to heal.
  6. Cut off large branches in stages.  Large branches have a tendency to break off before they are cut though and tear off the bark below the cut. Large branches can also be very difficult to remove from the plant once cut off.
  7. Cut back to an outward facing bud to encourage on open branch structure.

Wound paints.

Years ago it was the norm to treat all pruning cuts with a wound paint. This fell from favour and the accepted wisdom became that all they did was seal the diseases in nice protected environment so their use has stopped. The accepted best practice is now to avoid painting anything on pruning cuts and allow the plants natural healing processes to act.

Tools.

The only tools needed are:

  • Secateurs – pick a well made pair that are comfortable in your hand and keep them clean and sharp. These will do most of you pruning.
  • Loppers – sometimes called parrot bills due to the shape of the cutter on some models. Used for branches too thick for secateurs but too thin for a saw. Looked after a good pair will last many years.
  • Pruning saws – these come in a wide variety of shapes and sizes. Pick one that feels comfortable and replace it when it becomes blunt. Do not try to cut too thin a branch with a saw, if you can cut it with a pair of loppers use them. If you are doing a lot of pruning the battery powered reciprocating saws with a green wood blade make very good pruning saws.
  • Pole loppers – these are loppers on a long, sometime telescopic pole, and they allow you to cut high branches from the ground. These come into there own when pruning fruit trees.
  • Chainsaws – it will be rare, if at all, that one of these will be needed as they are for cutting large amounts of thick timber. They are expensive to both buy and maintain, as well as being very dangerous pieces of equipment. If you really think you need one make sure you are familiar with there safe operation.

Hedge cutters

These are possibly the most dangerous tool in the garden. They are designed to prune hedges, just hedges, and where there is large area of formal hedging to be kept in shape they save a lot of work. That said some of the most extensive and impressive formal hedging you will see is in formal French gardens and I have never seen a powered hedge cutter used there, just hand shears. Anything else the French view as sacrilegious.  The problem is when people get into their heads that they are a pruning tool. They are not! I have sadly seen some dreadful examples of butchery as the result of a hedge cutter wheeling gardener.

Clematis "Multi Blue"
Clematis “Multi Blue”

Pruning table

As a general rule:

  • Spring and winter flowering trees and shrubs tend to flower on the previous summer’s growth so prune immediately after they finish flowering in spring.
  • Summer flowering trees and shrubs tend to flower on current summers growth so prune them in winter when the plants will not be encouraged to produce soft growth which will be susceptible to frost damage.
  • Be cautious cutting into old wood as not all plants will produce new shoots from it.
  • If you have to remove large branches bare in mind their cuts will take longer to heal.
  • If in doubt phase drastic pruning over time.

Below is a table of some common plants with details of there specific pruning needs.

Plant Frequency Timing How
Berberis - deciduous When too large or congested. Can be thinned after flowering, but best pruned in February. Thin congested branches and shorten them to a where they branch. Will generally come away from old wood.
Berberis - evergreen When too large or congested. Can be thinned after flowering, but best pruned in April. Thin congested branches and shorten them to a where they branch. Will generally come away from old wood.
Buddleja davidii Annually for best flowering. March. Cut back hard.
Clematis – large flowered hybrids which are expected to flower their main flowering before mid-June Annually. February to March when the buds are plump and green. Cut out any dead wood and shorten the remaining vines to the first pair of plump buds.
Clematis – main flowering is after mid-June Annually. February to March. Cut all the shoots to 1 metre or less above ground level.
Clematis – spring flowering Only if space is limited. Immediately after flowering. Cut out all the shoots which have flowered.
Cornus - grown for their coloured winter stems Annually, for best winter stem colour. Early spring. Cut back hard.
Cotinus When too large or congested. Early spring. Cut back to within 2 or 3 buds of old wood.
Cotinus "Royal Purple" - if grown for large foliage Every one or two years Spring Cut hard back to near ground level.
Deutzia Annually for best flowering. Immediately after flowering. Cut out some old wood lose to the ground to encourage new growth.
Escallonia Annually. After flowering in autumn. Cut back old flowering growths. Can be hard pruned at the same time if too large.
Eucalyptus gunnii – grown for its round juvenile foliage Annually Once frost have finished in early spring Cut hard back to near the ground level.
Ficus carica (fig) – fan trained Twice a year End of June and November End of June: Pinch out the growing tips of the young shoots on the frame work of branches. Tie in the resulting shoots. November: prune back half the fruited shoots to 25mm. The remining shoots should be tied in parallel to the wall, spacing them 20 to 30cm apart. Do not allow the framework to become too crowded as the young growth and fruits need plenty sunshine.
Forsythia Annually. Immediately after flowering. Cut back flowered shoots to encourage strong new growth lower down which will provide next spring’s flowers. Aim to remove about 20% of the old wood.
Garrya elliptica When it is becoming too large. Spring Cut back as necessary.
Hydrangea paniculata and H. arborescens Annually. Spring For more prolific flowering prune prune back to a healthy pair of buds 25 cm above the ground level (up to 60 cm if you wish to form a taller bush).
Hydrangea – climbing Annually. After flowering. Cut back over long shoots but try to retain the top grow as this is where most of the flowering occurs. Drastic pruning should be done over three or four years to minimise the reduction in flowering.
Hydrangea – shrubby Annually. Late winter to early spring. Cut one or two of the oldest shoots to the ground to promote new growth. Mopheads are best dead headed in spring to protect the terminal buds but Lacecaps can be dead headed immediately after flowering.
Hypericum calycinum When looking tired. Winter Can be cut down to the ground and top dressed with a general fertilizer.
Hypericum “Hidcote” When it is becoming too large. Winter Shorten outermost shoots back to sides shoots to hide cuts.
Lonicera - climbing and flowering later, on the current seasons growth When it is becoming too large. Spring. Cut back any shoots which are becoming too long.
Lonicera – climbing and flower early on the previous seasons growth Annually. Late summer immediately after flowering. Prune back by a third.
Lonicera – shrubby ones used for hedging Three times a year. Spring to autumn. Trim to maintain shape. Neglected specimens can be cut hard back to 150mm high.
Lonicera – winter flowering When too large or congested. Late spring immediately after flowering. Prune shoots flowered shoots to new growth and remove about a fifth of old wood to promote new shoots.
Mahonia When too large or congested. Once flowering is finish in spring. They flower on the ends of shoots so shorten them to bring the flowers nearer to the ground. Come away from old wood well.
Malus domestica (apple): Bush – spur bearing Annually. November to early March. Shorten last season’s shoots by one third.
Malus domestica (apple): Bush – tip bearing (e.g. 'Blenheim Orange', 'Bramley's Seedling', 'Discovery', 'Lord Lambourne', 'Worcester Pearmain') Annually. November to early March. Cut back a proportion of older fruited branches to a strong younger shoot positioned closer to the to the main trunk or higher up the branch. This will reduce congestion and prevent branches becoming too long.
Malus domestica (apple): Restricted as cordons, espaliers, etc. Annually. Mid to late August, when the bottom of the new shoots are stiff and woody. New shoots are stiff and woody along their bottom third, with dark green leaves and a cluster of leaves at the base. 1. Cut back new shoots (laterals) more than 20 cm (8 in) long growing from the main stem to three leaves above the basal cluster of leaves. Do not prune new shoots that are less than 20 cm (8 in) long as they usually terminate in fruit buds 2. Cut back new shoots growing from existing side-shoots (sub-laterals) to one leaf above the basal cluster 3. Remove any upright, vigorous growth completely 4. If secondary growth occurs after summer pruning, remove this in September. If this is a persistent problem, leave some longer shoots unpruned as these will draw up the sap and grow at the expense of secondary growth elsewhere. Cut these back to one bud in spring, as well as any vigorous growth projecting above the level of the supporting wire.
Osmanthus When it is becoming too large. After flowering in spring Shorten outermost shoots back to sides shoots to hide cuts.
Populus × jackii 'Aurora' Annually. Late winter. Prune hard to promote new shoots with larger variegated foliage.
Potentilla When too large or congested. Spring. Cut back to tidy up, but remove avoid cutting into old wood; apart from the odd shoot to encourage new growth.
Prunus avium (Cherries: sweet) Annually. Early to mid-summer. Fruit on one year and older wood so aim for a balance between existing fruiting shoots and their replacement. Do not winter prune to reduce the risk of silver leaf and bacterial canker.
Prunus cerasus (Cherries: acid) Annually. Late summer. Fruit on previous seasons wood, so aim to balance last year’s fruiting wood with this year’s growth which will be next year’s fruiting wood. Do not winter prune to reduce the risk of silver leaf and bacterial canker.
Prunus domestica (plum) When the crown needs thinning. Spring. Cut back as necessary.
Pyrus communis (pear): Bush – spur bearing Annually. November to early March. Shorten last season’s shoots by one third.
Pyrus communis (pear): Bush – tip bearing Annually. November to early March. Cut back a proportion of older fruited branches to a strong younger shoot positioned closer to the to the main trunk or higher up the branch. This will reduce congestion and prevent branches becoming too long.
Pyrus communis (pear): Restricted as cordons, espaliers, etc. Annually. Mid July, when the bottom of the new shoots are stiff and woody. New shoots are stiff and woody along their bottom third, with dark green leaves and a cluster of leaves at the base. 1. Cut back new shoots (laterals) more than 20 cm (8 in) long growing from the main stem to three leaves above the basal cluster of leaves. Do not prune new shoots that are less than 20 cm (8 in) long as they usually terminate in fruit buds 2. Cut back new shoots growing from existing side-shoots (sub-laterals) to one leaf above the basal cluster 3. Remove any upright, vigorous growth completely 4. If secondary growth occurs after summer pruning, remove this in September. If this is a persistent problem, leave some longer shoots unpruned as these will draw up the sap and grow at the expense of secondary growth elsewhere. Cut these back to one bud in spring, as well as any vigorous growth projecting above the level of the supporting wire.
Ribes - flowering When too large or congested. Immediately after flowering. Remove any weak shoots and prune some shoots hard down to ground level to encourage strong new growth.
Ribes - foliage Annually or biennially. Early spring. Cut hard back.
Ribes uva-crispa (gooseberry) - bushes Annually Winter Remove dead and low branches. Prune side shoots to one to three buds and shorten branches to one third.
Ribes uva-crispa (gooseberry) - cordons Twice a year Early June to mid-July and then Late Autumn or Winter Early June to mid-July: cut the side shoots back to five leaves and tie in the leader to its cane. Once it reaches the top of the cane at 1.7m cut the leader back to five leaves back from the end of last year’s growth. Late Autumn to Winter: after the leaves have fallen cut the side shoots back to one or two buds and cut the leader back by one third until it reaches the end of its cane. Once it does cut the leader back to one to three buds back from the start of last seasons growth.
Rosa: Shrub, standard, climber. Annually. February to March. Reduce by two thirds. see How to prune a rose bush.
Rubus fruticosus agg. (Blackberry) Annually. Winter. Remove the fruited canes and tie in the new ones.
Spiraea - spring flowering e.g. S. ‘Arguta’ When too large or congested. Immediately after flowering. Cut back the shoots that have flowered while retaining as much of the new growth as possible as this bares next spring’s flowers.
Spiraea - summer flowering e.g. S. ‘Anthony Waterers’ and S. ‘Goldflame’ When too large or congested. Early spring. Flower on current seasons growth so cut back to within 2 or 3 buds of the old wood.
Syringa Annually Immediately after flowering Remove old flowering wood. It may be necessary to pinch over vigorous shoots in summer and remove suckers from grafted plants.
Viburnum – grown for their berries. (e.g. davidii) When it is becoming too large. Late winter. Reduce as needed.
Viburnum – spring flowering (e.g. x burkwoodii carlesii, opulus and rhytidophyllum). When too large or congested. Late spring or August, but not so late that new growth will not time to ripen before winter. Remove weak shoots and shorten others back to a manageable size.
Viburnum: winter flowering When it is becoming too large. Spring. Reduce as needed.
Weigela hybrids Annually. Immediately after flowering. Thin crowded bushes and remove a couple of old branches to ground level to encourage new shoots.

For more information on specific plants see:

  • Clematis by Christopher Lloyd
  • The Old Shrub Roses by Graham Stuart Thomas

How to Plant up an area with grown cover shrubs

Hydrangea macrophylla 'Merveille Sanguine'
Hydrangea macrophylla ‘Merveille Sanguine’

The secret to making a low maintenance garden border is to start off with no perennial weeds, after that the maintenance is no worse than a lawn in the first couple of years and far less thereafter. When creating a border most people make the mistake of making it too narrow, a 300mm (1 foot) deep border will just not work. If that’s all you can manage your better off with climbers or wall shrubs. 1.5 to 2 metres (5ft to 6ft 6inches) is the sort of depth you should be aiming for, not all gardens may be able to accommodate this but the closer you can stretch to this the better. In a very small garden you may do better having one deep border at the bottom of the garden and climbers and wall shrubs on the other walls.

Urtica dioica (Stinging Nettle)
Urtica dioica (Stinging Nettle)

Once you’ve chosen your area you need to remove any perennial weeds before you start to plant. Removing them once the plants are in and growing is far harder and the reason many peoples’ borders fail to work. Weeds like couch (Elymus repens ), ground elder (Aegopodium podagraria) and stinging nettles (Urtica dioica) have a spreading root which can quickly grows through the root ball of newly planted shrubs making the weeds extremely difficult and sometimes impossible to get rid of. Where the area is an established lawn these weeds will have not been able to become established because of the regular mowing. Here the grass can be stripped off but some weeds will be left behind such as dandelions (Taraxacum species) with their deep tap-root. The most reliable way is to kill off all the vegetation with a glyphosate weed killer (sold as Roundup, Gallup and other brand names). Leave the weeds to die down, this

Elymus repens (Couch grass).
Elymus repens (Couch grass).

can take a week or two and then turn the ground over with a garden fork, removing any roots and large stones. If the border is edged by a lawn, tidy up the edge to form a clean line and spread 25 to 50 mm (1 or 2 inches) of organic matter and use a garden fork to combine it into the soil. If the soil is very sticky with clay, mix some sharp grit (about 1 to 4mm) to open the soil up making it better draining, easier to work and with more air in it.

The source of the organic matter is not important so long as it’s free from contamination and weeds, your choice can be bases on price and availability. Well-rotted garden compost is ideal but few gardens have a large supply of it, peat was the traditional alternative and although it is a good soil improver these days its environmental cost makes it undesirable. Many councils now sell recycled waste as compost and these are normally well made, just don’t pay a premium for an “organic” label it does make the compost any better; just allows the seller to claim a higher price! If you live in a rural area you may be able to get farm yard manure and if rotted down this is very good, but in practice farms don’t want to leave the manure heaped up for a year or two to rot down so if you are going to use it you may have to except you must leave it to rot down before you can use it or the rotting straw can soak up any available nitrogen.

Photinia 'Red Robin'
Photinia ‘Red Robin’

You are now ready to plant the border. Choose shrubs which have a good dense canopy of leaves in summer so they smother any weeds before they can become established. Being evergreen is not important in this context as weeds germinate doing spring and summer, but some will provide some interest during the winter. Try not to focus on what’s in flower at the time as you want as long a period of interest as possible and bear in mind foliage lasts a lot longer than flowers. When walking around the nursery or garden centre make use of the labels and staff, if they’re not helpful go somewhere else! A good supplier will take pride in their stock and gave a good knowledge of it. Deciding how far apart the plants should be is tricky and it can be very difficult to visualise how big a plant will be in a few years’ time. The tendency is to over plant, especially in small areas so have a look at the label and ask if in doubt. Also bear in mind a 1.8 metre (6 foot) high plant is generally going to end up as wide as it is high.

Skimmia japonica 'Bowles's Dwarf'
Skimmia japonica ‘Bowles’s Dwarf’

Once you made your choice and paid for them pack them in your car carefully, DO NOT have them sticking out of sunroofs and windows, they will travel perfectly well laid on their sides; even if some end up gently laid on top of one another. When home get them out of the car as soon as possible, stand them in a sheltered corner and water them well. Like this, so long as they are keep watered they will be fine for up to a week if you run out of time.

Planting can be done on any frost free dry day and start by setting out your plants in their intended positions. Now is the time to make any last-minute adjustments to the arrangement before planting.

Viburnum davidii
Viburnum davidii

To plant use a garden spade to dig a hole larger than the plant pot, remove the pot, place the plant in the hole and firm the soil back around the root ball with your heel, making sure the top of the compost is level with the border soil. To remove the pot grasp the plant where it emerges from the compost and give the rim of the pot a firm tap with the palm of the hand. After all the plants are in rake over the surface to tidy up and water the plants really well, in part to settle the soil in around the root ball.

Give the borders a quick check over once a week for any weeds emerging, and remove them; most weeks there will be nothing to do and the next spring feed them with a general fertilizer.

Cornus controversa

Cornus controversa 'Variegata'
Cornus controversa ‘Variegata’

Best known in gardens in the form of Cornus controversa ‘Variegata’ this plant has had a convoluted history. The species C. controversa Heml. was first “discovered” in cultivation. In January of 1909 an article was published in Curtis’s Botanical Magazine which discussed the naming of Cornus macrophylla and the authors noted that there appeared to be confusion regarding the name. Though introduced back in 1827 it was not widely grown but it was known to be a tall and bushy plant when observed in the wild and this varied little over it wide natural range.  William Botting Hemley who had retired as Keeper of the Herbarium and Library at Kew the year before had studied this and noted that the examples in cultivation were a mixture of two species: one with opposite leaves and the other alternate.

Cornus controversa 'Variegata' foliage
Cornus controversa ‘Variegata’ foliage

The simple fact was that the naming had got into a mess but when the original specimen that Wallich had named C. macrophylla was checked it had opposite leaves and the original description in Flora indica of 1820 described the leaves as “sub-opposite”. Next Meyer in 1845 had also described the plant in a Saint Petersburg publication but naming it C. brachypoda. All this resulted in America and continental Europe using Meyer’s name of C. brachypoda for the form of the plant with opposite leaves and C. macrophylla for the alternate leafed form while in Britain both forms were known as C. macrophylla. In an attempt to clear things up the German botanist Bernhard Koehne tried to split the species in the belief that the Himalayan form was a distinct species which he called C. corynostylis but got confused between the opposite and alternate leaf arrangements. To clear up this confusion William Hemley proposed that if the plant had its leaves arranged opposite one another on the branches it should be called C. macrophylla Wall. as has been Nathaniel Wallich’s intention and the alternate leafed form should be a separate species Cornus controversa Hemsl. meaning cornus controversial, a most appropriate name. And that is as it has remained; apart from an attempt to place several of the cornus species, this one included, in the genus Swida in the 1960’s.

Cornus controversa 'Variegata' foliage close up
Cornus controversa ‘Variegata’ foliage close up

That would be the end of it with C. controversa Hemsl. providing us with a very garden worthy small tree with tiered branches and masses of cream flowers in May, but towards the end of the 19th century a variegated from was found and shortly before 1890 Veitch Nurseries introduced it as Cornus brachypoda ‘Variegata’. Now known as Cornus controversa ‘Variegata’ this is a plant which stands out to gardeners and non-gardeners alike. Smaller growing than the original but retaining the tier arrangement of branches, the leaves are longer and narrower and tend to be asymmetrical in shape with an irregular creamy-white margin. Known by the common name The Wedding Cake Tree its hardy in the UK and was awarded an AMG by the RHS in 1993.

Its size and shape means it is best suited to a larger garden where it has room to grow and show off its tiered habit and would look particularly effective in a large border with an under planting of spring bulbs. The flowers are followed by berries and on some soils attractive autumn foliage. The plant is often produced by grafting and so care should be taken to watch out for suckers from the more vigorous rootstock which need to be removed as soon as seen.

Viscum album

Viscum album
Viscum album subsp. platyspermum on limes trees at Hampton Court Palace, London

Mistletoe has fascinated humans for millennium, many plants have superstitions attached to them but mistletoe seems to have attracted more than most. It’s not hard to understand that a clump of evergreen leaves growing out of dormant tree in midwinter would grab the imagination. The druids are said to particularly venerate mistletoe growing on an oak tree, something it rarely does, harvesting it with a golden scythe on the 6th day after a new moon. Consisting that the plant is woody and gold is an extremely soft metal I not sure how true that is and as they left no written records of themselves this could just be dramatic invention. It still plays an important part in culture with the tradition of kissing under the mistletoe at Christmas but the plant is poisonous with a few berries bring on stomach ache though serious poisoning is rare.

Viscum album is wide spread across Europe and it has over the centuries been seen as a cure of a vast range of ailments right up to the present time. Diokorides (the 1st century AD Greek physician) reported that Hippocrates (in the 4th to 5th century BC) believed mistletoe could be used in the treatment of complaints the spleen and menstruation. Over the following centuries it has been recommended as a treatment for swellings, tumours, epilepsy, infertility and ulcers. In more recent times people have tried to use is to treat hypertension and cancer.

Viscum album
Viscum album (Mistletoe)

The genus Viscum L. contains about 100 spices but only V. album L. is native the UK and then mainly in the south and midlands. In naming Viscum album L.. Linnaeus took the Latin for mistletoe as the genus and album, no doubt referring to the distinct white berries, for the species name and listed it in volume 2 of his Species Plantarum. The genus Viscum L. is presently in the family Santalaceae along with 6 other genera. The common name Mistletoe comes from the old English mistel and many semi-parasitic plants around the world have the same common name. It is also known as including All-heal and Masslin in England and has many other names across Europe, Germany having a particularly large collection of names for it.

Mistletoe is notoriously difficult to establish and the species is now divided into 3 sub-species depending on the host plant it lives on.

Viscum album subsp. abietis (Wiesb.) Abrom. which grows on Abies species.

Viscum album subsp. austriacum (Wiesb.) Vollm. which grows on pine trees and very rarely on spruce.

Viscum album subsp. platyspermum Kell. (subsp. album) which grows on hard wood trees.

This goes in part towards explaining why it is so difficult to establish mistletoe as the sub-species are very specific to their chosen host but there also appears to be genetic factors as not all potential host can be infected with equal ease. For example, oak is rarely infected but even then there is a wide range of how readily a plant will be infected with a particular oak species. Therefore, where a plant has only a few mistletoe plants on it not become host to a lot and only specimens with a lot of mistletoes will host a lot.

Mistletoe is evergreen with tiny flowers that are insect pollinated and would never be noticed; the insects are attracted by the sweet smell . The male and female flowers are on separate plants with about 4 times as many female plants as male ones. The plants flower between the end of February and April  and the fruits (or berries) appear from October to May with Mid-March to mid-May being the best time to sow the seed, making sure to brake the outer coating and allowing the sticky contents to help the seed adhere to the bark of the host tree.

Mistletoe is a parasite, all be it a partial one, taking water and minerals from the host tree and this weakens the tree. Infected apples trees will yield between 7% and 56% less depending on how vigorous the rootstock is, with the plants growing on the more vigorous rootstocks affected the least. Once established the Mistletoe shoot doesn’t divide for the first 3 or 4 years then each year the shoot divides in two, ultimately reaching about 1 metre across, so giving a very rough and ready guide to its age.

 

Prunus laurocerasus

Prunus laurocerasus foliage
Prunus laurocerasus foliage

The cherry laurel is one of the most widely planted screening plants in gardens having reached western Europe by the end of the 16th century and is recorded in cultivation in Britain in the 17th century. It has been cultivated that extensively its geographical origins seem to be a little hazy but would appear to stretch from the east coast of the Adriatic sea eastwards along the south coast of the Black seas as far as the Caspian sea.

It is hard now to appreciate the effect that this plants arrival would have had in western gardens at the time of its arrival. Gardens at the time would have had very few evergreen bushes and along comes this large vigorous bush with its mass of large smooth shiny evergreen leaves. Added to this is the masses of white flower spikes in late spring and the small black fruits in autumn. Few plants offer such a range of attractive features. Sadly now it has been relegated to being a plant of little garden value.

Prunus laurocerasus flowers
Prunus laurocerasus flowers

This is in part because we have so many more plants to choose from now but also it has been a victim of its own success. It has been over planted in the past because of its appeal as a fast growing evergreen leading it to being used where a fast evergreen hedge is wanted’ a role it isn’t really suited to. Its large leaves look tatty and unattractive when it is cut with shears or a hedge cutter and it should really be cut back with secateurs. If you must have an inappropriately fast growing hedge you are better with × Cupressocyparis leylandii. On the rare occasions it is allowed to grow unmolested it makes a fine large flowering shrub in a large garden. Unfortunately it most often ends up crammed into far too small a space with its hacked leaves blacked at the cut edges. I have seen examples of people trying to grow it as a 600 mm high by 300mm wide hedge, something such a large and large leaved plant will never do successfully and which there are far more appropriate plants for.

Prunus laurocerasus 'Castlewellan'
Prunus laurocerasus ‘Castlewellan’

In most cases the form Prunus laurocerasus ‘Rotundifolia’ is grown in place of Prunus laurocerasus having leaves half as broad as long and a yellower green than the species. Other cultivars of note are Prunus laurocerasus ‘Castlewellan’ (syn. P. ‘Marble White’) a less vigorous plant with white marbled leaves, Prunus laurocerasus ‘Otto Luyken’ )a low shrub with upward pointing leaves and stems and Prunus laurocerasus ‘Zabeliana’ a low horizontally branching shrub which makes excellent ground cover even under the dripping shade of trees.

Prunus laurocerasus fruit
Prunus laurocerasus fruit

Along the way it acquired a variety of names until Linneaus set it as Prunus laurocerasus L. in the 1753 in the first volume of Species Plantarum. Prunus is the Latin for a plum tree which is in the genus and laurocerasus comes from laurel, the Latin for laurel, and cerasus, the Latin for cherry. This and the common name reflect the small round black fruits which resemble cherries. These cherry like fruits or their common name of cherry laurel should not lead you to believe the plant is in any way edible. All of the plant is poisonous and the reason you do not hear of people being poisoned by it is because you will be very ill before you have chance to eat sufficient to poison yourself. These poisonous chemicals are also the ones which produce the almond smell from the crushed leaves. That said this has not stopped people from trying to use it as a quack medicine. Laurel water was used for various treatments but is basically a solution of hydrogen cyanide of varying concentration and so extremely dangerous.

Actinidia kolomikta

Actinidia kolomikta foliage
Actinidia kolomikta foliage

This beautiful wall shrub deserves to be far more widely grown yet currently only about 53 suppliers are listed in the RHS plant finder. This is surprising as few other wall grown plants provide such an attractive display for so long. The foliage opens green but quickly develops a white and pink variegation as if they had been dipped in pots of white and pink paint. This variegation only develops in the presence of plenty of sunlight and along with the shrubs scrambling habit means it is always seen grown against a south facing wall, although I can imagine it would also be very attractive scrambling over a south facing bank.

Actinidia kolomikta growing against a wall
Actinidia kolomikta growing against a wall

It’s white, slightly fragrant, summer flowers are over shadowed by the foliage and as it is both dioecious and it is only the male plant which appears to be in cultivation you are unlikely to see the fruits which are said to be edible. The closely related A. deliciosa (A.Chev.) C.F.Liang & A.R.Ferguson which is better known as the kiwi Fruit and several of the 100+ species of Actinidia Lindl. are cultivated commercially for their fruit.

Actinidia kolomikta (Rupr. & Maxim.) Maxim. is easy to grow not being particularly fussy as to soil type and vigorous, reaching up to 4.5 to 6 metres up a wall. They are reasonable easy to propagate by cuttings or layering and are perfectly hardy.

Actinidia kolomikta grown as a shrub
Actinidia kolomikta grown as a shrub

First described by Carl Johann Maximowicz and Franz Josef Ruprecht two botanist working in Saint Petersburg in the 19th century; they initially placed the plant in the genus Prunus but subsequently both revised their decision and Maximowicz placed it in the genus Actinidia created by the British botanist John Lindley which he named after the Greek for ray because of the styles in the flowers. The plant is native to the region of Amur in Russia where it is known as kolomikta and Maximowicz described the plant growing wild in his 1859 book Primitiae Florae Amurensis (Beginnings of an Amor Flora). Amur Oblast is still a largely remote region with temperatures that can range from above 30°C in summer to below -40°C in winter.

How to cut back over grown shrubs

Before reaching for the pruning tools you need a clear idea of what you are hoping to achieve and in the context of this post it is a healthy plant which fits, both physically and aesthetically into its location in the garden. When you have finished you want something which does not overwhelm the area around it or look unattractive to the eye.

Pruning is not the easiest of things to teach, partly because of the different requirements of different plants but equally because it is as much art as science. To start with a few preliminaries:

  • Plants don’t always respond well to pruning – not all plants will come again if you cut into old wood, this includes nearly all the conifers but also a number of others.
  • Those that do, don’t always do as you expect – often a plant will respond to pruning by producing a mass of soft shoots rather than one or two useful ones.
  • Once you’ve cut it off you can’t put it back – so if in doubt delay cutting and then take off a bit at a time to see how it looks
  • Think ahead to prevent accidents – you would be amazed at the number of people who actually cut off the branch they are sitting on!
  • Make sure you are suitably equipped – as you will never make a tidy job using poor/blunt tools.
  • Plan first, act second – have a really good look at what you’re tackling and how your cuts are going to affect the plant before you do anything.

The first step is to remove any dead and diseased material, the second remove crossing branches and the final one is to shape the plant.

Any dead or diseased parts of the plant are going to be no benefit to you or the plant and if not yet diseased it probably soon will be. Yes that branch may be in just the right place for what you wanted but if it not healthy it’s never going to look right and will end up causing problems further along the line so cut it back to healthy growth just above a bud or close to where it branched off a larger part. If it’s a larger branch do it in three stages to prevent it damaging the rest of the plant when it breaks away from the plant. Work methodically, starting with the larger branches so that any damage caused by removing them can be cleared up as you go.Branch pruning

Once we’re left with a collection of healthy branches we can turn our attention to any which are crossing through the bush. This is not a hard and fast rule as the first but  there are reasons for it. First such branches almost always end up rubbing against one another as the plant moves in the wind. This causes the bark to be worn away at these points and it is the bark which acts as the plant’s main defence against diseases getting in. This means that sooner or later these places will be where problems are going to occur. The second reason is that plant diseases tend to benefit from a still moist atmosphere and this is more likely to occur in a tangle of branches than a nice open structure which the air can move  through freely. Finally it tends to be more visually pleasing not to have a lot of branches crossing through.

Now we can come to shaping the plant and this is much more a matter of personal taste.There are though a few things to consider. If by nature it’s a big plant and you are going to cut it down a long way , then it will quickly re-grow and you will soon need to repeat the process. Should you allow it more room or is it simply not in a suitable place? If you are trying to lower the height of the plant, remove the tallest branches completely low down where they divide and allow the shorter branches which are left to form the new top. Nothing looks worse than just choosing a height and cutting everything off in a level line at this height, but you regularly see this done and often by people claiming to be professional. Once done the plant is very unlikely ever to recover aesthetically.

The important thing is to take your time and regularly step back to get an overall view of the job as you go. Whatever plan you start with you will have to fine tune it as you go as the job progresses and new ideas occur.

Buddleja davidii

Buddleja davidii 'Burgundy'
Buddleja davidii ‘Burgundy’

Buddleja davidii Franch.is a popular garden shrub which has escaped cultivation to become established as a naturalised plant in the wild, where it can often be found on waste ground around towns and cities. It will grow happily in most garden soils and can even be seen growing out of cracks in masonry on buildings. It does prefer a sunny position as none of the buddlejas do well in shade. It grows well in even poor soil sending up long arching branches which are topped by the flowers in ranged in a cyme in late summer. Being a late flowering shrub it responds to early spring pruning and when pruned hard in March it produces far more flowers. These flowers give it its common name of butterfly bush as there strong scent is irresistible to butterflies.

Buddleja x weyeriana 'Honeycomb'
Buddleja x weyeriana ‘Honeycomb’

Its ease of cultivation and natural variability has lead to a host of named varieties being selected and introduced varying from white through to purples and very dark blues. The RHS plant finder currently lists 121 different ones, including some which are forms of Buddleja x weyeriana – a hybrid between B. davidii and B. globosa.

The genus Buddleja L. was named by Carl Linnaeus in ‘Species Plantarum’, naming it after the Reverend Adam Buddle but of reasons unknown he spelt it with a “j” when strictly speaking it should be spelt with an “i”. This has lead to considerable confusion over the

Buddleja davidii 'Harlequin'
Buddleja davidii ‘Harlequin’

years but as he repeatedly spelt it this way that is how it should be spelt. The only Buddleja known to Linnaeus was B. Americana L.which William Houstoun had sent back to Europe from the Americas and even then the spelling was causing confusion as in one of his illustrations he spelt it incorrectly both times even though he attributes the naming to Linnaeus. The species B. davidii itself was first sent back to Europe from China by the French Catholic missionary Armand David having found it in  August of 1869 and  Adrien René Franchet working in the herbarium of the natural history museum in Paris published a description of it in 1887 naming it in after the discoverer.

Buddleja davadii 'White Profusion'
Buddleja davadii ‘White Profusion’

 

 

 

 

 

 

 

References:

Species Plantarum by Carl Linnaeus

Hillers Manual of Trees and Shrubs

Excursion flora of the British Isles by Clapham et al

Nouvelles Archives Du Muséum D’Histoire Naturelle series 2

Reliquiae Houstounianae sive Plantarum in America meridionale … Collectarum Icones by William Hostoun

The International Plant Names Index (2012). Published on the Internet http://www.ipni.org [accessed 12th December  2012]

Tropicos, botanical information system at the Missouri Botanical Garden – www.tropicos.org [accessed 12th December  2012]

The Royal Horticultural Society Horticultural Database’, available at www.rhs.org.uk [accessed 12th December  2012]

Fatsia japonica

Fatsia japonica
Fatsia japonica

One of the classic garden plants for shade Fatsia japonica is much admired for its large, glossy, evergreen leaves and easy temperament. It grows happily in any reasonable garden soil and does particularly well in shade, though not so well in dry shade. It is also tolerant of a maritime garden though its large leaves will need some shelter from strong winds. The large fleshy leaves evoke the image of lush tropical rain forests but the plant is reliably hardy, though the result of crossing it with ivy produces the less hardy x Fatshedera lizei. Quickly forming a medium sized shrub with flowers borne on the end of the shoots. The flower buds and white flowers look a lot like a scaled up version of Ivy flowers, appearing in autumn. This late flowering means though the buds are reliably formed in the UK the flowers are often damaged by frost.

Fatsia japonica leaf
Fatsia japonica leaf

Known by a variety of common names including Japanese aralia, castor oil plant, fatsi, fig-leaf palm and glossy-leaved paper plant; F. japonica was originally described by Carl Peter Thunberg in 1780. This followed his trip to Japan where it grows wild and he named it Aralia japonica. It was re-named in 1854 by Joseph Decaisne and Jules Émile Planchon, two botanists working in France. They took it out of they genus Aralia and created the new genus Fatsia for it; so the name is now Fatsia japonica (Thunb.) Decne. & Planch.

In the wild Fatsia japonica is found from central Japan south along the Japanese islands almost to Taiwan and in South Korea. It is sometimes described as a monotypic genus, meaning that there is only one species init, but in fact there is at least two other species of Fatsia, Fatsia oligocarpella Koidz. and Fatsia polycarpa Hayata.

Fatsia japonica 'Variegata'
Fatsia japonica ‘Variegata’

It was introduced to western horticulture in 1838 and though the plain green Fatsia japonicais the one most often seen in gardens others are available and the variegated form Fatsia japonica ‘Variegata’ which has splashes of white on the leaves is worth looking out for.

 

Hydrangea aspera

 

Hydrangea aspera
Hydrangea aspera

The rough leaved Hydrangea is one of the less commonly grown examples of this important genus in our gardens, but makes an excellent addition to the garden. The large velvety leaves provide an attractive display all summer covering this medium sized bush. And come June and July this is topped with dark lilac “lacecap” flowers. As is typical of Hydrangeas Hydrangea aspera D.Don is easily grown and need a shady location, making it ideal in front of a north facing wall or fence, or in the shade from trees. It is a very variable species and some people have questioned its hardiness but I have seen it grown successfully all over the UK. That said it probably benefits from some protection, particularly from strong winds which would damage the leaves, though this protection could easily be provided by the fences around most gardens or by a woodland aspect.

Hydrangea aspera flower
Hydrangea aspera flower

An oriental species it is found growing wild in the Himalayas, West and central China,Taiwan and Myanmar (Burma). It was first described by the Scottish botanist David Don in his 1825 flora of Nepal, placing it in Linnaeus’s genus Hydrangea L. In gardens it is often represented by Hydrangea aspera D.Don ‘Macrophylla’ a sterile selection with large leaves and flowers.

The variability of Hydrangea aspera D.Don, probably due in part to its wide geographical distribution, has lead to a degree of confusion regarding the different subspecies, cultivars, etc. The RHS database lists about 38 different entries under Hydrangea aspera D.Don including several subspecies. I it is doubtful how many of these are valid as the International Plant Names Index (IPNI) does not recognise any valid subspecies of H. aspera,raising them to the level of species.

Hydrangea aspera foliage
Hydrangea aspera foliage