Head Gardeners’ tips
May 2024

There is much to do but the longer warmer days make the graft a gift. Gentle jobs like tidying up spring flowered clematis, and tying in other climbers, are absorbing and relaxing. Bigger tasks such as pruning spring flowering shrubs can be done now too. There’s a small window for this in Scotland, so get to them right after flowering to ensure all the energy goes into the new growth you want and isn’t wasted. Shrubs like Ribes, Spiraea, and Weigela can be trimmed to shape, and try to remove a third of the oldest stems to encourage fresh growth from the base. This renews the plant and prevents it from getting too woody and congested. A good feed and mulch after pruning is best.

While you’re out with the secateurs, it’s also a good time to take softwood cuttings of shrubs such as Fuchsia, Hydrangea, and Lavender. Choose pencil sized stems of new growth and cut off below a leaf joint. Strip the bottom half of its leaves and nestle these cuttings around the edges of pots of free draining compost (1:1 ratio compost to sharp sand is ideal). Water well, cover to retain moisture, and set in a warm sheltered spot to root. Once the roots start to show through the bottom of the pot you can move the new plants out into individual pots to grow on. Take extra and share with friends!

Many seeds can still be sown in the garden and greenhouse, but best get cracking. Vegetables such as beans, beetroot, kale and carrots can be sown direct into prepared beds or large pots. Cucumber, coriander and courgettes can still be started indoors. In the garden, Foxglove and Honesty can be seeded direct into the borders. These biennials will flower next year and provide wonderful winter structure as well. They both love a shady woodland aspect, and in urban gardens I think they’re lovely sown along the driplines of hedges. Once established, these plants will self-seed and create lovely little colonies.

Be wildlife and waterwise in the garden this month. Collect rain and grey water where you can and choose drought tolerant plants for dry areas instead of reaching for the hose. Many people are putting away their mowers for May, so think about cultivating a mini meadow in your lawn too. If your soil is too rich for standard meadow seeds, try ox eye daises (leucanthemum vulgare), field poppy (Papaver rhoes) and yarrow (achillea millefolium). These do well even in our damp Scottish clay and can add a touch of whimsy and biodiversity to the long grass. Meadows are now one of the rarest and most threatened habitats in the UK and we desperately need to increase these precious, species rich reserves.

If you often enjoy your garden at the end of the day, reward yourself by planting some night scented flowers. Annuals that can be grown from seed, like Night Scented Stock, Mattihola longipetala, and Nicotiana, are great additions to a twilight garden and can be direct sown into pots of moist, well drained compost this month. Add a fragrant climber like native honeysuckle, Lonicera periclymenum, and you’ll also benefit the night flying moths and thus the bats as well. Pale flowers are favourites of the midnight garden gang, and your garden will be luminous and irresistible.

This is the last month we need to watch for frost, so prepare the area that you will be planting out your tender plants and erect your sweet pea structures in readiness for the all-clear. These can be as simple as a few bamboo canes tied at the top to make a tripod, with twine coiled around between the canes for the pea tendrils to hold onto.

Remember that indoor grown plants need to be hardened off to acclimatize to the strong wind and sunlight before being planted out. This should take a week or two and don’t rush it or all your hard work will be ruined.

At the end of the month, don’t forget that you can cut back certain perennials to get sturdier and more floriferous plants. Called the ‘Chelsea Chop’ (also my Covid haircut!) it can be useful for plants that are a bit too tall for their neighbours, or who tend to flop once grown. Plants that respond well include helenium, campanula, phlox and asters among others, and all it entails is cutting the whole plant back by a third early in their growth. They will flower slightly later but will be more compact and reduce the need for staking. You can also just pinch the tops of some stems, leaving some to flower earlier, and some to flower later.

Whatever you do in the garden this month, be sure to stop and soak in the sunshine and enjoy what you’re creating. It’s about the journey not the destination.