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.

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Autumn Tidy Up

A leaf on a lawn covered by frost

A leaf on a lawn covered by frost

With the arrival of dark mornings thoughts turn to tidying the garden up for winter. The first frosts will soon finish off the annuals and tender perennials, while the hardy perennials die back for the winter and the deciduous trees and shrubs will take on their autumn colours before dropping their leaves.

Any tiding up will invariably create a collection of rubbish and gardening is no different. It’s often said “one man’s rubbish is another man’s treasure” so what treasure can we find before glibly throwing everything in a skip. Not everything is going to be re-usable; if you come upon what might be asbestos sheets, then only option is to contact your local authority for some specialist advice. That aside in most cases the limiting factor is your imagination.

Once you get rid of the bits of broken glass and rusty metal, which only the most artistic gardeners will be able to find a use for, you are left stones, rubble, lumps of wood, leaves, weeds and  other bits of greenery, and soil. As a rule its best to keep any topsoil you find surplus to you immediate needs. Small amounts of topsoil often come in handy for filling stump holes and the like but, due to its weight small quantities are hard to come by and expensive. Even if you have nowhere to store it, you can lose it by spreading on to the borders. If you think this is going to cause problems consider 50 kg of topsoil (the same weight as 2 bags of cement) will cover a patch 1.5 m by 1.5 m with a layer only 10 mm thick.

Shrubs in Autumn

Shrubs in Autumn

 

The green material will make good compost so long as care is taken when making it, and you have a little space for a compost heap/bin. Any woody material, like rose prunings, are best off shredded if they are to breakdown in a reasonable time. If you do not have the space, or time, our local authority will have a green waste composting service which will do the work for you and provide a quality controlled produce you can buy back from them when you need it.

It you have a lot of trees and shrubs you a likely to find, come autumn, you have a lot of dead leaves in the garden and these make an excellent soil improver in the form of leaf mould. Its worth considering that evergreen plants also shed lots of  leaves through the year, just take a walk through a conifer wood one day! Leaves tend to rot down more slowly that most of the green waste that goes into compost, so it’s often better to separate the leaves out. The leaves can be heaped up into a simple container made of course wire netting supported by posts or canes, just consider how you will get the leaf mould out again. As the leaves of different plants will rot down at different rates is best if the tougher leaves are shredded to help them brake down, and some people recommend adding some grass cutting to help the process along. The heap should not be allowed to dry and will need turning at least once. After a year you will have a very useful soil improver but ideally the heap should be left for two years.

Olearia x macrodonta

Olearia macrodonta bush

Olearia macrodonta

The “New Zealand Holly” rightly earns is common name; its pointy edged leaves make look a lot like a grey holly leaf. They can be a little tender but are sufficiently tolerant of salt laden winds that that do well near the coast. This makes them a valuable plant in seaside gardens where their tolerance of salt and the relative absence of hard frosts makes them well suited. In all but the most exposed gardens they can be grown; coming through all but the worst winters with little or no damage. They are very wide spread in North West Scotland, to the point of almost being naturalised.

Olearia macrodonta bark

Olearia macrodonta bark

While evergreen like holly; the leaves are not as hard and vicious as holly (as anyone who has hand weeded around a holly bush will testify too). It also differs from Holly in that it grows quickly; forming a medium sized bush, and given time a small tree. Holly on the other hand is rather slow growing.

In summer the New Zealand Holly is covered by mounds of white flowers and older specimens develop a peeling, almost shaggy, bark which new growths breaks away freely.

Close up of Picture of an Olearia macrodonta shoot

Olearia macrodonta shoot

As the common name suggests it is a plant native to New Zealand and was first described by Joseph Dalton Hooker who in 1864 named it Eurybia dentata var. oblongifolia. This turned out to be incorrect and in 1884 John Gilbert Baker, working at Kew under Hooker, renamed it Olearia macrodonata. Though this is the name it is normally grown under in the UK; the New Zealand government’s own data base lists it as Olearia ×macrodonta Baker a hybrid between two species: O. ilicifolia and O. arborescens.

Though Olearia ×macrodonta is widely grow in the UK, the dwarf form Olearia macrodonta ‘Minor’ would be well worth seeking out for a court yard garden or rockery. This plant looks like a miniature version of the original, being smaller in all its parts, and it is listed in the RHS Plant Finder.

Olearia macrodonta 'Minor'

Olearia macrodonta ‘Minor’

 

Cutting back – the call to arms

Pruning is cutting back for the plants benefit while cutting back is pruning for the gardeners benefit so certain rules apply to both. First remove dead and diseased material, second remove crossing branches and finally shape the plant.

Any dead or diseased parts of the plant are going to be no benefit to you or the plant. 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.

How to cut off a large branch

How to cut off a large branch

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.

Clearing out

Now we’ve given the garden a really good looking at it is time to get our hands dirt. Having studied the garden you may well have come to the conclusion some plants are just too big, in the wrong place or you just don’t like them. To start with the last first, because it’s the simplest, you’ve got one choice and that is to dig it out. At this point you may come to the conclusion that it would be just as easy just to cut it down to the ground and leave the roots where they are. This though has problems and first of these is that stumps take a VERY long time to rot. Not years but decades! You are then going to be left with a stump in the border to try to disguise, trip over every time you go into the border and hit with a spade when you try to dig in the border.

There is a further problem to this short cut because not all the fungi that will attack and hopefully rot down the stump are benign. Some will spread to adjacent plants and attack them and one such example is Honey Fungus. I’m not going to digress into details of this disease except to say once you’ve got it you have a serious problem.

Pedestrian Stump grinder

Pedestrian Stump grinder

This means, if at all possible, you are going to have to dig the plant out. This can be achieved in a number of ways and the easiest is often a stump grinder, or chipper, which grind the stump down to a heap of chippings. These come in a vast range of sizes from small ones you can hire to operate yourself and wheel around the garden to large self propelled machines which are supplied with a specially trained operator. An alternative is to use a digger to dig out the stump. These are rarely a good solution unless one is already on site for other reasons due to their size, cost, difficulty of operating and limited ability to dig out stumps – I’ve seen a JCB struggle to remove  relatively small tree stumps. Third way is winching out the stumps and the modern lever operated winches do make this a more attractive option than most people realise. They have though two Achilles heels. One they need a very secure anchoring point as how ever much force they pull the stump with they also pull what ever they are anchored to. The second is as they pull the roots out anything else near them, like drains, water pipes etc, tend to be pulled out as well. Finally you can grab the bull by the horns and just dig it out by hand. Be warned though this is very hard work. You will need to good spade, gloves, boots, axe and preferably a large steel crowbar.

Acer palmatum var. dissectum

Acer palmatum var. dissectum

Acer palmatum var. dissectum

Acer palmatum var. dissectumis a much used garden plant where something striking but delicate is wanted. Much loved in “Japanese” style gardens where it mixes well with gravel and boulders, a position which allows it to be ground in isolation so as to show off its dome of draping branches.  They are slow growing bushes slowly forming a small shrub after many years.

Acer palmatum var. dissectum foliage

Acer palmatum var. dissectum foliage

Not fussy plants they will grow in most decent garden soil though they do best in moist but free draining soils. The finely divided, thin leaves are prone to damage by wind and sun so they are best in a sheltered part of the garden with light shade, but not heavy or dry shade.

Known as the Cut Leaf Japanese Maple due to A. palmatum being known as the Japanese Maple as it comes from Japan, central China and Korea and its leaves being finely divided. The naming of Acer dissectum is confused, a situation caused at least in part by confusion between botanical names and those of cultivated plants. It is often named as Acer palmatum ‘Dissectum’ but that would only be if the plant did not exist naturally in the wild, as that form of name is only used for a cultivar. Things are further complicated by the many cultivars of Acer palmatum var. dissectum which have been raised and are available, Acer palmatum var. dissectum‘Garnet’ being a particularly nice example with red tinged foliage (this being an example of a cultivar of a variety).

Acer palmatum var. dissectum 'Garnet'

Acer palmatum var. dissectum ‘Garnet’

Acer palmatum var. dissectum 'Garnett' foliage

Acer palmatum var. dissectum ‘Garnett’ foliage

Soft Landscaping

This loose term is more frequently seen used within professional horticulture but simply means the soft things that grow ( i.e. plants) and the soil or compost they grow in. So it includes trees, shrubs, hardy perennials, grass, etc.. It generally doesn’t include vegetables grown purely for consumption, there are a number of very ornamental vegetable that would then be soft landscaping, as commercially a landscaper would not normally be involved in vegetable growing, just providing space for their cultivation in a garden. Commercially vegetable growing would be something undertaken by a market gardener which has nothing to do with landscaping.