Garden School:


Garden School:
Teaching this week: Rose pruning (as always!) and leaf mold.

Thursday, 10 May 2012

Circular growth, Purple Hazel and Oak v Ash

I'm sure you've read this many times in gardening books: "after a few years, a perennial will lose vigour and will need to be lifted and split. Discard the centre section, and replant strong new sections from around the edges."

Some while ago I wrote about a Solidago (goldenrod) clump that was doing its best to form a circle but had been thwarted by the nearly Yew hedge, so it only grew in a semi-circle. *rummages through earlier blog entries: nope, can't spot it, sorry. Haven't time to read each entry - golly, what a lot I've written! Memo to self:  must make blog titles more descriptive of what they contain.*

Last week I spotted this growth ring in a patch of Lysimachia ciliata purpurea:


How's that? Nearly a perfect circle!

I brought these plants into this garden about two years ago - the dark purple, and the height, are perfect for the composition.

But look how neatly they are demonstrating the "grow-in-a-ring" principle.

This clump - and several others just like it - started off as sturdy plants in 2 litre pots, and they have spread themselves superbly.  So much so that I am now able to dig out sections, and move them to other parts of the bed, to enhance the effect.

I love a certain amount of purple in a garden - I think it breaks up the "green" monotony if there are not many plants in flower at a particular time, and it provides a lovely backdrop for something feathery and green -  like Cosmos foliage, for example.

My favourite purple-leaved plants have to include Physocarpus opulifolius "Diablo", (right) - a fabulous and under-used shrub.

I have these for sale but I am secretly hanging on to a few for myself.. . wonderful foliage, and it also does rounded clusters of pinky-white flowers, but I grow it for the foliage.  Great name, isn't it? Physocarpus is just a name, but "opulifolius", well, that's clearly opulent foliage, isn't it? And "Diablo" just reeks of the devil, wouldn't you say? So it's devilishly opulent - irresistible.

I also love Cotinus coggyria "Royal Purple", the purple-leaved Smoke Bush - again, I grow it for the foliage, and luckily all of my clients who have this shrub think the same, so I get the opportunity to give them a really hard prune every spring, for the really strong flush of those lovely round leaves, all through the summer.

Today I have been potting up a batch of purple leaved Hazel - Corylus avellana purpurea - which I'm planning to grow on, and eventually plant out in a double line to make a walkway.

I'm lucky enough to have a friend who has several mature trees of this tree, and they seed themselves liberally throughout her garden. She kindly invites me to turn up with my fork in spring, and to help myself to as many as I can find and retrieve.

This is so much more reliable than collecting and planting acorns - you can assess the depth of colour of the new leaves, and reject any that are a bit too much on the green side.

We discussed, today, the question of whether the variability occurs because the purple hybridises with the common green, or whether the purple merely has very variable seedlings.  As we can't realistically insulate the purple ones from every green one for miles around, we will probably never know!

This friend also reminded me of the old country saying about forecasting the summer based on which trees achieve leafage first, Oak or Ash.  The saying goes something like "Oak before Ash, we're in for a splash: Ash before Oak, we're in for a soak."

As a modern interpretation of this saying, I wondered if it should be updated to "Leaves on suckers, get out your Muckers, Leaves on crown, prepare to drown." ha! ha!

I did a little research on the subject, it transpires that it is not an accurate saying: the Woodland Trust have been checking records over a period of 158 years, and apparently it is usually Oak first, and it does not appear to have any connection to the amount of rain in the following summer.  In fact, Oak trees are sensitive to temperature, so they don't put out their leaves until we reach a certain degree of warmth (which could explain why there are none to be seen on any tree round here) but Ash respond to the amount of hours of daylight, so they tend to put out their leaves very much at the same time each year.

So much for country lore, huh?

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