Everything is taking off, but beware a late frost
April’s frosts and strong winds have been tough on the soft spring growth in my garden, leaving some herbaceous perennials looking battered and bruised, slowing growth and really drying everything out.
Thankfully no serious damage has been done and the recovery is already underway. I can’t wait for the soil to disappear this month beneath a carpet of vibrant green foliage, punctuated through my borders with the tall purple drumsticks of Allium ‘Purple Sensation’ and the raspberry red thistles of Cirsium rivulare ‘Atropurpureum’.
Don’t rely on May for entirely clement weather either, however, as nights can still be frosty right up until the end of the month – and beyond in some areas. Only plant out halfhardy summer bedding, including pelargoniums and petunias, and tender vegetable crops like French beans, courgettes and tomatoes, when the weather is warm and you’re confident that the risk of frost has passed. Keep potting up any young vegetable plants on your windowsill into larger pots so that their growth isn’t checked while they wait to move outdoors or into an unheated greenhouse. I usually sow French beans, courgettes and squashes on a windowsill in the second week of May to plant out in early June, once they have been hardened off.
Outside in the vegetable plot, earth up potato plants by drawing soil into a ridge around their stems as they grow, to protect them from frost and encourage a heavier crop. Hardier crops should be growing well, but also need a little attention; weed around plants to reduce competition, thin out dense rows of seedlings gradually to the recommended spacing, and pinch out the tops of early-sown broad bean plants when the first pods form to prevent blackfly infestations. Continue to make small successional sowings of a range of fast-growing salad and baby root crops for a steady supply through summer.
Elsewhere in the garden, tie climbing plants into their supports with soft twine as they grow rapidly. Flourishing weeds can easily be kept under control by nipping out with a hoe once a week and it’s a good idea to watch for the first signs of pests and diseases as you work around plants, because squashing small clusters of aphids and picking off the first spotted leaves can help prevent problems spreading. Prune Clematis montana and early-spring flowering shrubs once their displays are over and cut back fuchsias, Caryopteris and penstemons to keep them compact and flowering freely. The foliage and spent flowers of Pulmonaria and Doronicum can also be cut back to the base to produce a fresh flush of foliage for summer.
Only plant out tender vegetable crops when the risk of frost has passed