May Garden To Do List

May is my favourite month in the garden. So full of optimism of the year to come, this is the month when the garden really takes flight. With March giboulées and April’s occasional storms, increasing soil temperatures and day length nearing its peak, the garden appears to grow before your very eyes. As the Alliums and Camassia come to the fore so too do the early flowering perennials for the start of a spectacular annual show.

Don’t let the garden get away from you by following your May garden to do list:

Lawns

Continue mowing regularly. The lawn will be growing very rapidly now and may even require cutting twice a week if you like to keep your lawn really neat. If you aren’t already, start cutting with a mulching setting: the clippings will help to retain moisture in the lawn. Frequent mowing will keep the clippings small and prevent them smothering areas of the lawn, which will create gaps.

Avoid temptation to give your lawn a short back and sides. Higher summer temperatures are on the horizon and if you want your lawn to persist for as long as is practicable without excessive irrigation then cut on a high setting.

If you lust after a manicured green sward, you may wish to apply lawn fertiliser early this month. It is very possibly the last chance to do so before the drought of summer.

Box hedges

Remember to inspect your box hedges for box tree moth caterpillars. If you identify its caterpillars are present the preferred option is to remove them by hand and dispose of them. For small topiaries etc this is practical. For large hedges treat with Bacillus thuringiensis (a natural soil-borne bacteria) to kill caterpillars. Apply the treatment in the early morning to prevent it from evaporating before it can take effect. Use only when box tree moth caterpillars are present to target this species only and ensure minimal destruction of other insects.

Use in conjunction with a pheramone trap to really interrupt the lifecycle of the box tree moth and maximise efficacy.

Weeding

Weeding is essential at this time of year. It can be a rather dull task, albeit necessary to keep the character of a planned planting. It has been said that a year’s seed is seven years’ weed so weed little and often. Keep at it throughout the month to really break the back of it and interrupt the weeds’ life cycle. If you mulched earlier in the year it ought to be not too difficult to remove any annual weeds that have appeared since then by hand.

Perennial weeds, such as bindweed or ground elder, are trickier, but not impossible. I’m not a fan of herbicides, but if you want to erradicate these weeds carefully applying a herbicide is the only practical way to remove weeds of this sort. Ensure it is a systemic herbicide that permanently kills the weed by the roots, rather than a weedkiller that simply kills the growth you can see above ground, or else the weed will simply return. Attempting to dig bindweed or ground elder out only chops up the roots and makes what was one plant, now several.

In the morning or evening (to allow the leaves time to absorb the herbicide before it evaporates) apply a systemic weedkiller neat to the top and underside of a few leaves with a small paintbrush. This ensures good application, minimises your herbicide use in the garden and minimises the risk of any spray drifting onto other wanted plants. Wear some old clothing with long sleeves to keep herbicide from contacting your skin.

In new plantings the weeds can be accessed easily. In established plantings, bindweed removal is more difficult. Try inserting a cane in the soil next to the bindweed and train it up the cane. Allow it to grow up the cane and away from your prize plants. Then on a suitably still day apply to the weed your systemic herbicide with a paintbrush, as above.

More than one herbicide treatment may be necessary. Allow the weed to die in situ. It looks tatty, but don’t try to dig it out once the top growth looks dead, the roots may still not be entirely dead and you may just end up spreading the weed making matters worse. Once truly dead it will rot away soon enough.

Herbaceous borders

Some perennials will flower a second time if cut back once the first flowering is finished. At the end of the month Nepeta and herbaceous Salvias may have been flowering for a month or so and their flowers may be almost entirely exhausted. If so, bite the bullet and prune them back at the end of the month to encourage a second flowering later in the year.

It is important to get to know your plant, as they can have different methods of pruning and not all perennials will flower a second time if treated in this way.

Nepeta fassenii (and its cultivars such as ‘Six Hills Giant’ and ‘Walker’s Low’) can be cut back almost entirely to the ground after the first flush of flowers. If you part the top growth you may very well see that there is fresh new basal growth already coming through the middle. Chop off all the top growth and water thoroughly. Within a month the plant will have regrown and all the new growth will be preparing to flower. Alternatively, for those not feeling so brave with the shears and with a little more time on their hands, you can selectively prune out the old stems back to the base leaving the turf growing through the centre to continue growing untouched.

Herbaceous salvias (such as Salvia pratensis or S. nemorosa) are similar, but don’t be quite so harsh with them. Simply cut off the spent flower heads back to just above a node about a third of the way down and the plant will produce further side shoots on which more flowers will form.

In the potager

Harvest ripe Cherries. Treat yourself and make clafoutis. Get to them fast before the blackbirds do!

The risk of an overnight frost has now passed so sow directly tender crops such as sweetcorn, tomatoes, aubergines, pumpkins/squash now, or buy plantlets from the garden centre and plant them as soon as you can so they can benefit from the moisture in the soil before the hot summer drought arrives.

Plant of the month

Left to right: Bee orchid, lizard (or goat) orchid and the Charente orchid

So many plants come into flower this month, Alliums, Nepeta, herbaceous Salvias, Roses, Iris, Cow Parsley, the list goes on. But for me, the plant(s) of the month just has to be the native orchids. These are something that just aren’t seen in a typical UK garden and so for me they are quite special and fascinating. They are protected species and thrive in meadow grass free of herbicide. Care is simple, just leave them alone to flower and go to seed. Do not deadhead them. The late summer meadow cut will help disperse the ripe seed and increase your stock.