May your garden grow

It is hard to believe that it is already May and gardens and other planted spaces can seem to double in size when our backs are turned for just a few minutes. It can be no surprise that May is the favourite month for many gardeners as the garden is still fresh with emergent growth and flowering promise and very little is in decline.

Seasonal superstars

Lilac flowers

Lilac, Syringa vulgaris, FraukeFend, CC0

Gardens are in full force this month with the flowers of many plants in bloom or emerging. These include the deceptively dainty looking Clematis Montana flowers borne on their rampant and vigorous climbing stems; the distinctively elegant, hanging flowers of Wisteria; the cheeky trumpets of columbine, Aquilegia sp., the intoxicating scent of lilac flowers, Syringa sp. and Mexican orange blossom, Choisya ternata and the cheering purple globes of the ornamental alium, Allium Hollandicum ‘Purple Sensation’. Gardeners with acid soils may be treated to a showy display from the vividly coloured Azaleas and Rhododendrons.

With all of this growth, colour and nectar the garden wildlife is upbeat and working hard; pollinators are fluttering and buzzing away collecting nectar and pollinating plants; caterpillars are beginning to emerge and looking for a snack; birds are singing throughout the days whilst foraging for food for their fledgling chicks. Pause a moment and appreciate the cycle of life that is beavering away. But then let’s join in and get back to work.

Spring pruning

It’s time to prune back spring flowering shrubs when they have finished flowering such as Bachelor Button’s, Kerria japonica, and the flowering currant, Ribes sanguineum, to tidy them up and let them put on growth for next years flowers. Firstly prune out old and dead wood and crossing or congested stems. For Kerria prune back all shoots that have flowered either to ground level or to a strong side shoot, whilst aiming to maintain an even form. For Ribes, cut back ¼ of the oldest branches. These shrubs can be renovated if they are very old and congested by cutting back all stems to ground level. It seems brutal and not all shrubs respond well to such extreme treatment, which is hardly surprising as to have gotten to that point they will be old and tired, but many will be given a much needed boot up the backside and will reward the hard shearing with refreshed and invigorated growth.

It can be an onerous job but get those box hedges, balls, cones and triangles and whatever other box topiary forms there are, pruned into shape. It is often a fiddly job as hand shearing is better than a bruising mechanical trimmer but if the trim is kept close to the desired shape it should hopefully not need to be done again until mid – late autumn. Best to prune on a still day to prevent the cuttings from flying away before they can be collected – no, really, do not get any ideas about simplifying the clean up as most neighbours would not be grateful for the extra clippings to clear from their gardens!

Support climbers and taller plants

Cane grid support

Cane grid support, Elaine Hughes , CC BY-SA

Early May is a good time to stake or support tall, fleshier herbaceous perennials such as delphiniums and mullein, verbascum sp. to encourage their emergent foliage to grow through and envelope the supports to create a more natural display. Indeed, some supports such as ornamental wire frames or grids or cane or metal wigwams or cloches are positioned to become a focus of a bed, adding visual structure to the scheme as well as support to the plants within it. Either way, without them it is possible that taller plants or flowering stems may collapse or snap in wind or rain and be ruined. Another potential bonus of plant supports is that they may protect a plant from the whimsy of clumsy pets who are unaware of the etiquette of not tearing through a planted bed. Or maybe that is just a problem I have with my pesky puppy?

It can be tricky to retrospectively stake a flopping plant without making it look like a restrained and bedraggled creature. If plants have already leapt ahead and it is too late to stake them it is worth trying to strategically place canes or sticks around the plants so that they have at least a little support. If all else fails it is also possible to cut the offenders back hard to let them grow up again in a more supportive, staked environment yet with time still to flower this year, albeit a little later. Better that than a bed full of collapsed, broken or restrained flowers.

Keep an eye on the weather

Mexican orange blossom, Choisya ternata

Mexican orange blossom, Choisya ternata, DEZALB, CC0

Despite the onward momentum into summer the air can still be chilly in places so be aware of the potential for night frosts, which can damage blossoming fruit trees overnight and destroy the season’s crop, as well as those tender plants such as petunia, begonia and lobelia being hardened off outside. A clear sky at night may be one sign of an impending frost. If you get caught out and a plant that has been hardening off takes a frosty hit try to let it thaw out as slowly as possible – perhaps by locating it to a shadier spot.

Just a few dry days or a light wind can dry the soil out fast so it is important to keep newly planted shrubs and perennials irrigated. Watering in the early morning or evening will reduce water evaporation further than if watering in the heat of the day. Mulching around the plants base with a well rotted organic material, such as manure or soil conditioner or even a few cms of grass clippings will help to retain soil moisture. Be sure not to touch the plants stems with the mulch as the rich material may burn and rot the stem.

Get some gardening inspiration

There is never a bad time to visit other gardens to get inspiration for planting choices and combinations as it is valuable to see plants throughout their growth stages across all of seasons. May is a really good time to see many gardens approaching their peak flowering point. The National Open Gardens Scheme lists gardens open across the country week by week. The Chelsea Flower Show in London kicks off the show garden season and is well worth a visit to see a huge range of plants in situ in the show gardens as well as the bouffant flowering displays in the pavilions. If, like me, it is hard to resist buying just a few more plants to squeeze into the garden then leave credit cards at home.

Task List for May

  • Prune back spring flowering shrubs when they have finished flowering such as Bachelor Button’s, Kerria japonica, and the flowering currant, Ribes sanguineum, to tidy them up and let them put on growth for next years flowers.
  • Prune box hedges, balls, cones and triangles into shape. It can be a fiddly job but keep the cut close to the desired shape or the plant using hand shears ideally.
  • Evergreen hedges in general will benefit from a tidy up this month to maintain their health and form. Mechanical trimmers are fine for the job.
  • Stake or support tall, fleshier herbaceous perennials such as delphiniums and mullein, verbascum sp. to encourage their emergent foliage to grow through and envelope the supports to create a more natural display. Use ornamental wire frames or grids or cane or metal wigwams or cloches depending on the plant and the desired effect.
  • Keep newly planted shrubs and perennials irrigated. Watering in the early morning or evening will reduce water evaporation further than if watering in the heat of the day.
  • Hanging baskets and container grown plants will most likely need increased watering. Do not be fooled into thinking that rain will help. Rain water will most likely to wash away from leaves and over the edge of the container leaving the soil dry.
  • Thin out annual plants such as sunflowers, Helianthus annuus, Cosmos, Cosmos bipinnatus, and night scented stock, Mattiola incana, that have been sown in situ to prevent them getting crowded and leggy. Thin out to one healthy seedling per 10-15 cm depending on anticipated growth of the plant. If done carefully enough the rejects could be transplanted elsewhere.
  • Continue to deadhead spring flowering bulbs such as daffodil, Narcissis, and grape hyacinth, sp. The directs energy to energise the existing bulbs for next years growth and away from creating new bulbs from the flowers.
  • Keep a weather eye out for any late frost forecasts to protect tender plants with a protective covering and bring in or shelter any plants that are hardening off outside.
Elaine Hughes

ELAINE HUGHES

Elaine is an RHS Gold Medal award winning landscape designer with a special interest in creating beautiful and functional spaces that are also as biodiverse and sustainable as possible. She has designed a wide range of projects including private gardens, community gardens, public areas, schools and community sites.