May is the first month of the year when leaves have fully emerged, on deciduous trees and shrubs, and all remnants of winter are banished. Sometimes it’s hard to think of this month as still being ‘spring’—the ‘RHS Chelsea Flower Show’ (running from 19th to 23rd May this year) was originally the ‘Great Spring Show’—especially when there can be periods of intense sunshine with high temperatures. There really is very little excuse not to go out and enjoy your garden when it should now be full of life and interest.
It’s coming to the end of spring bulb flowering and soon they will be dying down. In the past a lot of gardeners did weird things, like tying daffodil foliage into knots, in the name of ‘tidiness’ but, if you want to maximise your flowering chances next spring, applying a feed, while they are still in leaf, and removing their spent blooms is best practise. They may be a little untidy, while they die down naturally, but the trick is to plant them in areas of the garden where there is plenty of rapidly growing herbaceous, or shrubby, growth to hide their blushes.
The very earliest spring flowering shrubs can have their faded flower stems cut out now, on established specimens, because this will promote the growth of new stems. These mature, over the course of the year, and it is these stems which have the best flowering potential for next spring. Any shrub which is left unpruned will eventually get ‘out of hand’ becoming a congested mass of old stems with less and less flowering impact. The general rule of thumb is to remove approximately one third of the stems, excising the oldest first, annually once the shrub is mature and has reached the maximum size for its allotted space in the garden. You will soon get into a ‘rolling pattern’ of shrub maintenance, with each shrub being dealt with once its flowering period is over.
Something else which will require regular attention is weed removal. They will be germinating, growing and threatening to flower at a rate which increases exponentially with rising average temperatures. In the ‘bad old days’ regular applications of chemical herbicides would take care of weeds in places where there were no other plants, on drives, paving and gravelled areas for example, but now this is generally frowned upon and mechanical or manual removal is preferred. However you remove them, the name of the game is to be vigilant and to make sure you get to the offending weed before it gets the chance to flower and set seed. There is real truth behind the old adage; “one year’s seed is seven years weed”!
Of course, the readiness for weeds to germinate and grow rapidly is a signal that ornamental plants can also be sown and raised relatively easily from seed now. As well as hardy annuals sown in situ, where you want them to flower in the garden, you could also try sowing those biennial plants which need to establish this year in order to flower the next. Some useful spring flowering bedding, such as wallflowers, Bellis perennis and pansies, need to be sown pretty soon if they are to have a long enough growing period in order to flower from winter into spring next year. Don’t forget that bedding plants raised in your greenhouse, or on windowsills, will need a period of ‘hardening off’, bringing outdoors during the day but placed back under cover if night time temperatures take a tumble, before they can be safely planted out later this month.
Last month I wrote about the somewhat nebulous ‘last frost date’ but it’s worth remembering, although I think it’s less and less likely to have a frost in May, that tender plants cannot be planted outside, without protection, until all risk of damagingly cold overnight temperatures have passed. It should be pretty safe towards the end of this month, sooner if you keep some horticultural fleece to hand, to plant out any dahlias, or cannas, that you’ve gently woken up in frost-free conditions. Similarly tender perennials, such as pelargoniums (bedding geraniums) and the more exotic salvias, which you lifted and kept protected over the winter, can be planted out into beds or containers for their summer exuberance. The same is true for those bedding plants which you may have obtained as tiny plug plants, before it was safe to plant them out, but which you’ve grown on, probably potted into bigger pots, in readiness for planting out.
On things like pelargoniums and salvias, which have made new growth before planting out, it’s possible to cut off a few of the fresh, vigorous, new shoots and pot these up, under cover, in order to propagate new plants which will be useful to either increase your stock or to replace the oldest plants which you may have overwintered for many years but which will eventually ‘run out of steam’. It’s always a good idea to have a few new plants ‘up your sleeve’, and under cover, just in case you do get caught out with an unexpected cold snap, or other meteorological disaster, which kills your original stock plants.
I touched upon the need to deploy plant supports last month, favouring ‘pea sticks’, and if you didn’t manage that task in April then it really will need doing now. The aim is to get the supports in place, pea sticks can be woven into organic shapes, so that the herbaceous perennial grows up through the cat’s cradle of supportive twiggery. Trying to force tall growth, into a ‘corset’ of plant supports, is the horticultural equivalent of attempting to squeeze a ‘quart into a pint pot’; a mug’s game.
Elsewhere in the garden you should, by this stage of the game, be well into your routine of grass cutting, wherever you want a mown lawn and not a ‘flowery mead’. I’ve mentioned the need to keep weeds under control; alongside weed control comes pest control as these also have the potential to increase exponentially as temperatures rise. My own ‘bête noire’, although, infamously, red, is the lily beetle. I’ve seen these emerge as early as February, when we’ve had an unusually warm and sunny period, but this year I caught a mating pair on Fritillaria meleagris (Snake’s head fritillary) on 1st April. It’s worth checking for lily beetle on Fritillaria species as these are an alternative host plant, to lilies, and can allow for an even longer breeding season for these dreaded pests. I note that the ‘RHS’ have a dedicated site where you can report lily beetle sightings and even upload a photo of the offending beastie and what it was spotted on—happy hunting!
