May in the garden

This is a really burgeoning time in the garden. Despite a general trend towards more late flowering plant species, especially over the past few decades, at the heart of the ‘English Garden’ is the ‘cottage garden’ which is full of the kind of plants which bloom in May; irises, herbaceous geraniums, wisteria, roses, viburnums, peonies, alliums, etc. etc.
Another factor which makes May really special is that it’s the first month when every deciduous tree and shrub is truly in full leaf, in contrast to the raw nakedness of the winter months. This fresh foliage is yet to be ravaged by pests, disease or the slings and arrows of the Great British weather. Shrubs and trees grown specifically for their foliage, Japanese Acers being a prime example, are at their unspoilt best, clothed in a virgin set of lustrous leaves.
I generally consider May to be the first month when you can get days which feel properly warm and temperatures can occasionally climb to what could be described as ‘heatwave’ levels. This means that traditionally this is the month that frost-shy plants can be moved out of their winter quarters and back into the garden. It’s also the time when, even if you don’t possess a heated growing space, it’s safe to buy all those lovely, but non-hardy, plants to fill containers and bedding schemes with summer colour (but keep some horticultural fleece on hand in case a late frost threatens newly planted tender bedding).
Higher temperatures and lush growth increase the prevalence of pests and diseases. As always, the key is to nip any problems in the bud before they can escalate. Most indigenous pests, such as aphids, slugs, snails and their ilk, have natural predators which keep them in balance. Your early intervention is only required if the pest gets the upper hand and their natural predators need some help in reducing their numbers. The problem is with introduced pests, my own bête noire being the ‘Lily Beetle’, as they don’t have many natural predators and can therefore wreak real damage if they become established in your garden.
Adult lily beetles are bright red (as I hope you know by now seeing as I mention them every single year) which makes them easy to spot. They like to hide under the lily leaves, when not basking in the sun, and they are well-practised at dropping to the ground, if disturbed, where their black undersides makes them difficult to see. However, the main damage that they do is done by their larvae, nasty little grubs which cloak themselves in their own excrement. These voracious feeders can completely denude lilies, also fritillaries, so that the plants are weakened to the point of dying out over the years.
Just as pests can increase exponentially this month so can the weeds. Keeping on top of them is the key to success so regularly checking beds and borders, for newly germinated weeds, is essential. If the ground was cleared earlier in the year, mulched with a good few centimetres depth of sterile organic matter, then weeding is comparatively easy as new seedlings are easily pulled up if only rooted into the loose top layer.
Perennial weeds need digging out fully, including all the root, which can be tricky in a well-stocked flower border. If ever there was an excuse to use a targeted, glyphosate-based, weed killer then this is it. Apply it only to the offending weed, mixed at the recommended rate, with a paintbrush to avoid killing any nearby cultivated plants. I find dandelions, which have sown themselves right into the crowns of herbaceous perennials, are prime candidates for this forensic method of weed control.
Remembering that we had a hot, dry, spell last summer—now’s the time to test out any watering system that you rely on. This may mean investing in more watering cans, water buts, trickle hoses or anything that makes life easier for you in a heatwave. Water butts are all very well but they really come into their own if you invest in something like a ‘water butt pump’ so that you can still use a hose, or sprinkler, without access to mains water. I tend to use watering cans to water anything growing in a container because its much easier to tell how much water you’ve delivered, they need a good soaking, rather than with sprinkling with a hosepipe which can give a false sense of an adequate watering when actually you’ve barely wetted the surface.
Lawns should never be irrigated, it’s a waste of water, but regular mowing will be in full swing by now. ‘Little and often’ is paramount because allowing the grass to get really long, then shaving it to within an inch of its life, will weaken it and make it less able to cope with dry spells. Regular mowing also controls weeds by encouraging fine grasses, which are adapted to being constantly ‘grazed’, rather than coarser grasses and perennial weeds which could otherwise take over. Unless you are tending to a bowling green, it’s perfectly acceptable to have a few daisies, dandelions and clover in your lawn as they are important nectar source for many insects; a monoculture never exists in nature.
As mentioned at the start of this article, there is a profusion of flowering this month but many of the early flowering shrubs, the weigelas, deutzias, forsythias etc., can be just dull old blobs from here on in. Cutting out the oldest stems, after flowering, will keep them as productive as possible but once they are mature there is another way for them to earn their keep in the garden; use them as a support for a late flowering clematis.
The ‘Viticella’ group of clematis flower after mid-summer, on the current season’s growth, so they can be planted alongside early flowering shrubs and allowed to scramble through them. They flower when the shrub doesn’t, adding to its period of interest, and they are easy to manage because they can be cut to a few inches of the ground, before the host shrub comes into flower, each spring. A planting combination that makes full use of the space in your garden—what joy!