Garden School:


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

Friday, 30 December 2016

Garden Hygiene II: moving plants

I've already covered General Garden Hygiene, of self and tools, next time I'll be covering Disinfection, but for now we move on to the issue of moving plants between gardens.

This is a very large part of gardening: new plants are bought, old ones are lifted, split and given away, so there is a constant stream of plants coming in and out of the garden.

One of the biggest joys of gardening, to me, is the way that garden owners are so generous with their plants: I seem to spend a lot of time potting up divisions or cuttings to be given to neighbours, and of course, like all Professional Gardeners, I am forever bringing home poor sad orphans that I've been instructed to dig up and bin.  They are then nursed back to life and hopefully rehomed.

Also, if Client A is looking for a particular plant, and I happen to know that Client B has some, I can often arrange a swap.

So how do you avoid bringing pests, bugs, and diseases into your garden?

The first and most obvious is to always check incoming plants, whether bought or given, and in the case of plants which are particularly susceptible to problems, such as Box for hedging or topiary, put them into quarantine. Also, and I hate to say this, but if you know the garden from which they've come, and if you know that this garden has a particular problem, then consider if it is worth the effort to decontaminate the plant, or whether it is better to quietly "lose" it in the green waste bin or bonfire heap.

OK, "check all incoming plants", easy enough to say but what does this mean in practical terms?

When someone buys or brings in a plant, don't immediately plant it: take the time to have a good look at it.

Firstly turn it upside down over your potting table, or on the patio, and give it a good shake, to see if anything with legs falls out of the foliage.

Next, check the foliage: does it have notches (indicative of Vine Weevils) or brown patches which might be disease: are the leaves skeletonised, in which case there may be caterpillars still lurking on it: and so on.

Finally, de-pot it and look at the roots: are there any Vine Weevil grubs? Are there great gaping gaps in the rootball, indicating woodlice activity? Is it crawling with ants? Is it full of slugs? Is it so packed with roots that you can't see any soil at all between them?

Deal with these problems before putting the plant out into the garden, otherwise you are just introducing more problems. And when I say "deal with them...."

A. Things with legs fall out. Squish them. If they are Vine Weevils (matte black snouty things), scream loudly and throw the whole pot, soil and all, into the garden waste bin or onto the bonfire.

B. Damage to foliage. Assess it: notches = Vine Weevil, see A. Skeletonised leaves = caterpillars, check it very carefully and pick off all the little blighters. Squish them, or put them on the bird food table. Big 'oles in leaves and silvery highlights = slugs/snails, see B. Oh, this is B.Well, clean them off and squish them. Don't put them on the bird food table as slugs are quicker than birds. Well, you know what I mean - not "quicker" in the get-set-go! sense, but they'll have scarpered before the birds noticed they were there.

C. Depot and check roots. Vine Weevil grubs: see A. Ant infestation: see A. Full of slugs? See B, remove slugs. Ditto for woodlice - I really, really don't like them, but they don't (apparently) do much lasting damage to a plant, if you are about to plant it out in the garden. Although I would shake off as much of the soil as possible....

Right, you've checked the plant for nasty creepy-crawlies, you've discarded any that are polluted beyond redemption, and now you have either a nice plant, or a root-bound one. In both cases, I like to shake off as much of the original soil as possible. My reasoning is that the plant is going to have to get used to "our" soil sooner or later, and I'd rather it were sooner, on the grounds that if it's going to keel over, better to do it now, before I get emotionally attached to it. And if it's root-bound, then it will take forever to thrive if I don't help by unwinding and/or cutting off those gnarly, tightly-wound roots.

Box plants are a special case: now that Box Blight is running amok all over the country, you really don't want to accidentally bring it into your garden, so inspect Box plants particularly carefully. Look for any signs of brown patches on the leaves, or any spots or pustules on them - and don't forget to check the underside of the leaves as well. Push the branches apart so you can check the inner areas, too.

If you find any signs, look up "box blight symptoms" on the internet, and click on the Images tab, so you can see exactly what you should be looking out for.

Of course, there are things other than blight which affect Box - leaf miners, rust, to mention two - but frankly if you are bringing in Box plants to a garden, you are expecting to have them there for many years, so you really want to start with clean, healthy plants: so if they show any sort of damage to the leaves, reject them. Send 'em back! Demand a refund!

Even if they appear to be perfect, keep them in quarantine for a while - in the UK, the prevailing wind is from the south west, so put them in the north east corner of your garden, keep them watered and keep a close eye on them for at least 2-4 weeks, before planting them out. Why is the prevailing wind relevant? Because box blight is spread by spores: they splash up from infected soil onto the foliage, and they blow off and float away on the wind. So it makes sense to put the on the down-wind side of your garden so that any spores don't get spread across your entire garden.


These simple precautions should be enough to prevent unnecessary infections: there will always be something that slips through, but by checking, cleaning and quarantining, you should be able to prevent anything new appearing: and although it's easy to say "constant vigilance", but not so easy to do it, you can at least make it a regular part of your garden routine to walk round and look at your plants, to see if any of them are looking less than healthy.

The third and final part of this series, "Garden Hygiene III: first Sterilise your Secateurs..." is now published!



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