Tuesday 20 March 2018

Aim for amazing azaleas

Marie Staunton

Carefully prepared acid soil -- and hard work -- is the key to growing beautiful flowering shrubs, says Marie Staunton

I'm chasing my tail at the moment with all the extra work that needs to be done in the garden at this time of the year. And you would imagine that now wouldn't be the right time to be taking on new projects -- but I just can't resist rhododendron, and growing them in our garden means a lot of extra work for me.

But I'm up for the challenge and, hopefully, my new little plants will adapt well into their not-so-perfect soil conditions.

I envy those gardeners who can just go out to their garden, choose a spot, plant an azalea or a rhododendron and not bat an eyelid.

Acid soil is a godsend to those who love growing these beautiful plants and there are so many varieties to choose from.

There are a number of reasons why azalea and rhododendron leaves are yellow, and soil that is too alkaline will certainly cause this problem.

There are, however, a number of other reasons why this can happen.

Drought or poor drainage can be a contributing factor, so start as you mean to go on with these acid-loving plants and give them what they need. They require a soil pH of 4.5 to 5.5 and, if that isn't possible, you will need to create an acid bed for them.

My advice is to give them a good start because they aren't cheap, and you will waste precious time and money by cutting corners.

Make an acid bed at least 30cm deep and line it with a plastic membrane so that the alkaline soil in the other parts of your garden won't come into contact with it and lime water won't leach into it.

The same method applies if you would like to grow camellias or pieris, or, indeed, some heathers.

Rhododendron don't like it too wet or too dry, which is a bit tricky considering the plastic membrane, so you will need to find a way to let the water drain from the bed.

It is often a good idea to line only the sides of your acid bed to allow for drainage below.

Lime water normally leaches in from the sides and not underneath. I won't be too surprised if you give up on the idea at this stage and just resign yourselves to the possibility of never being able to grow them at all.

But where there's a will there's a way.

I'm only putting in a couple of azaleas and I plan to incorporate peat into the area and to top-dress yearly -- and to use an iron sequestrate and sing to them if necessary, to make them love my garden.

I will also have to collect rain water as they won't like the tap water on offer in North Co Dublin. I'm not too fond of it myself, so I am not surprised that it won't suit them either.

Feed rhododendron and azalea in early spring and through the early part of the summer, but not after that.

After all of that, I can choose my plants and settle them in and I particularly love the strong colour of the Azalea 'Hino-mayo'.

If you can get your hands on one, try a very new-to-the-market lime-tolerant rhododendron called Constanze 'Inkarho' which is a wonderful pink colour.

It can get to a height of around 1.5m.

These plants are produced on the 'Inkarho' rootstock which, after 20 years of research in Germany, has proven to be lime tolerant.

They will still require ericaceous compost and a good feed, but they will survive in a soil with a pH of 7 very well indeed.

Now for the 'shocker', which happens to be my little fella's favourite word at the moment, but I think it's appropriate in this instance: they cost upwards of €30 per plant -- for that price, it would want to have bells and whistles on.

Having said that, because there is no fiddling around with acid beds, it might be the answer for a lot of gardeners who simply want to grow a rhododendron without all the palaver.

A word of caution when planting -- they are all shallow rooters so don't plant them deeply; just to the same level as they were in the pot.

If you are interested in rare plants, you might like to head to Beaulieu House and Garden in Drogheda on May 13 for the Bord Bia-sponsored rare and special plant fair.

It starts early -- at 10.30am -- so, if you are after something a little bit different, then get there early and avoid the traffic because there are a number of events taking place in Drogheda on the same day.

See www.beaulieu.ie

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