The fast-emerging foliage of herbaceous perennials gives the May garden a freshness that is all too fleeting. However, it also promises a glorious flower display in the summer months. The speed of growth now also suggests that the danger of frost has passed, so tender plants and vegetables can be planted outside. Dahlia tubers can be planted directly into a rich soil and will soon start to sprout foliage. I tend to start Dahlias off in pots of compost however, in a cold greenhouse in early April, as the new shoots can be ravaged by slugs in open ground. Bedding plants such as Busy Lizzies, Petunias and Zonal Geraniums can also be planted out now. If you have grown them in a protected environment such as a warm greenhouse or conservatory, it’s best to ‘harden them off’ – this simply means get them used to the lower temperatures outside, by acclimatising them gradually. Usually this means popping them out in their pots during the day and bring them back in at night for a week or so. If you have a cold frame, pop them in there and merely close the vents at night.
It's hard to fit all the gardening tasks in during May – as it’s time to plant out tender vegetables such as runner beans, courgettes, and sweetcorn. Many vegetables can now be bought as young plants in the garden centre, which is especially useful if you only need a few plants, or don’t have the facilities to start from scratch. Salad crops should be sown in succession, to avoid gluts and to keep a supply coming. I always grow mixed lettuce and other salad leaves such as rocket, as this is the easiest way of always having something available, as it is picked little and often, rather than waiting for a single lettuce to mature. It’s way cheaper than the bags of mixed leaves in the supermarket, and much fresher – with no wastage! Several pickings can be had from a single sowing.
A job you should never leave too late during May is supporting plants – get stakes in around plants such as Delphiniums and Peonies; the foliage will soon hide the supports. Tie in clematis, sweet peas and other climbing plants as they grow. Trying to gather tall stems together later will only result in breakages or a ‘trussed up’ look. Clematis are extremely brittle so take care when tying in. Your hard work now will pay dividends later. Of course, following my own advice is another matter. I guarantee I will be frantically running around the garden tying plants up even in June!
JOBS IN THE MAY GARDEN
Earth up potatoes weekly, this supports the stems, excludes light from tubers and encourages spuds to form
Open greenhouse vents on warm days but close them at night
Prune stems of ribes (flowering currant), forsythia and choysia once flowering is over.
Clip evergreen hedges
'Harden off ' tender vegetables such as sweetcorn and courgettes and bedding plants like geraniums by putting them outside during the day and bringing them in overnight for a couple of weeks. They will get used to the lower temperatures and romp away when you plant out later this month.
