Summer Planting19th June 2006
Tracy Wilson considers the do's and don'ts of planting in hot weather
Planting at this time of year always seems fraught with danger because we’re dealing, usually, with a lack of water, which seems to be people’s biggest concern. But if you follow a few basic rules, there’s no reason why you can’t still plant at this time of year.
Indeed, very often this is when you find gaps in the garden: particularly when youíve got rid of your spring beds and you find that youíve got holes. Thereís nothing to stop you filling those holes up, but you have to bear in mind that anything you plant at this time will be wholly dependent on you for its water Ė whether itís in the initial planting method or whether itís thereafter.I can divide plants into two categories: those that are for Ďinstant gratificationí, shall we say, and those that are intended for greater longevity in the garden. So, for instance, we have bedding plants and biennials Ė or shrubs, perennials, trees, that sort of thing. If we deal with the annuals first, those ones are on the whole fairly cheap and cheerful. At this time of the year youíre not going to be buying the cheap strip bedding, in fact most of the small pack bedding will be more or less finished by now although you may be able to get some that are still looking nice. A lot of bedding plants will have been potted on into slightly bigger pots to keep them growing, keep them looking good and flowering well so that you can buy them full of flowers in order to take them home and create instant colour in your garden. But the same rules will apply, whether youíre planting something small or something large. The big trick is, when you prepare the ground, to dig the hole bigger than you need, fill it with water and let the water drain away. Then, plant your plant as you would normally, back-fill it and water it in very thoroughly. This means that youíre soaking the soil right around the root ball area and making sure that the whole of that area at the roots, where the plant needs the moisture, is wet to start with. Itís no good just dribbling a bit of water on the surface, it wonít do any good at all, youíve got to get down into the root system.
When it comes to planting perennials and shrubs, exactly the same rules apply. But normally, with plants that have a longer life-term, youíve got to bear in mind that any soil preparation that you do, youíve only got the one chance to do it right. With perennials, itís fairly easy to move them if you do make a mistake, but you do need to do as much soil preparation as you can. By incorporating green material into your soil, you will in fact improve the moisture retention and thereby help yourself and the plant: artificial watering is never, ever as good as making sure theyíve got adequate moisture at the roots to start with. So follow those fairly simple rules and youíll be fine. Thereís nothing to say that youíre not still going to need supplementary watering, and when you do, you do also run the risk of leaching nutrients out from the soil. This is much more of a risk in containers than it is in the ground, because obviously in the ground, nutrients come and go through the soil so itís a two-way process. Nutrients will leach out but the main thing is then to put them back in again, so make sure that you do top up the liquid feed, particularly for a container. So anything that you can do to put a little fertiliser back in, will keep your plants looking perky. In all honesty I would recommend watering once a week through the main flowering period for your plants in pots. Even for permanent pots like Camellias and Azaleas, Pieris (or any other permanent shrub you may have in a pot), a much weaker than normal feed but on a weekly basis, will keep them well.Pest control, when you are planting things in summer, can be a problem because in some respects youíre offering a fresh lunch to pests! So Ė particularly if youíre putting things out like perennials and bedding plants Ė there may be plants for which you might want to consider extra slug control. If you donít want to use slug pellets, which I admit I donít, you might prefer to use slug rings which are copper rings that will keep the slugs off them, or anything like that which might help. But sometimes you can go out, spend a small fortune on plants, put them out Ė and the next morning youíve got this delightful filigree effect, which really is such a waste, so you really want to be very careful. And do keep an eye out for other pests as well which have an effect through the summer: for example you may be looking at caterpillar invasions or vine weevil. Itís well worth thinking about the idea of biological control: these ones donít affect the plants, pets or any other wildlife in the garden Ė theyíre tiny bacterial controls Ė nematodes, as well as wasps, flies and other things that will actually parasitise the pests under question. Itís an interesting (and slightly vicious!) method of control which is actually much better for wildlife.It is important to encourage all sorts of wildlife into your garden. Itís also worth bearing in mind that you donít have to have a garden thatís got stinging nettles in or thatís jam-packed with plants that have berries, or anything like that. Any garden is good for wildlife and encourages it by providing a habitat, shelter, extra food. Because itís bringing insects in, itís bringing additional food in for any form of wildlife. Itís a big circle: everything comes round and goes round! Everything will benefit in the long run. Donít think youíve got to have a wonderful Highgrove-esque wildflower meadow to give yourself a good wildflower selection: itís seriously not true.
Perennials can be given the same treatment as anything else. You can certainly plant those at this time of year, it wonít cause any problem at all. I would happily think about putting those ones in. Itís also worth bearing in mind when you do buy perennials, you could think about Ďcheatingí and getting two for the price of one. A lot of perennials, if you buy them at this time of year Ė particularly ones that flower in the second half of the year. If you choose your plant carefully and have a look through it youíll probably find that you be able to drive a spade down through the middle and cut the clump in half without too much problem. It seems dramatic, and you might think youíre going to kill your plant, but in fact with perennials they can recover from that damage quite quickly when youíve done that and it will work very nicely. So it is worth doing, but I wouldnít recommend that you actually lift perennials and re-plant them in order to do that Ė that they wonít enjoy because youíll be disturbing the root system far more dramatically than with a potted plant when all youíre doing is severing it down the middle, which is an awful lot easier.
Trees are a different ball game. I would avoid planting trees at this time of year. If I were you, I would seriously consider leaving the trees until the autumn. They are going to be much more vulnerable to drying out, theyíll tend to be more stressed and in all fairness I would generally leave trees until September or October when theyíre starting to go dormant. The soil temperature then is still warm but the atmosphere is starting to cool down a bit and generally, I would say itís a much better time for planting trees