Gardening jobs for May

May can be a frantic month for a gardener. The to-do list of gardening jobs seems to get longer faster than you can tick items off. Don’t panic. You will just have to do the most important first, and the long evenings and milder weather mean this is probably one of the best months for spending as much time as possible out in the garden.

Gardening jobs in the veg garden

Harvest asparagus

Harvest asparagus

The taste of fresh, home-grown asparagus has to be one of the biggest joys in gardening. The flavour of some crops degrades rapidly a soon as they are harvested and asparagus is best enjoyed as fresh as possible. Harvest stems when they are as thick as a pencil by cutting them off just below ground level with a sharp knife.

Earth up potatoes

Earth up potatoes

As your potatoes are growing, draw the soil in from either side of the row to form a ridge that buries the stem of the plants. This will encourage the formation of more tubers.

Continual sowing of salads

Continual sowing of salads

For a constant supply of salad leaves through the summer you will need to sow regularly. Sow a pot or short row every 2-3 weeks through the spring and early summer. Take care not to sow when the weather is too hot though. High temperatures can inhibit the germination of lettuce.

Place pheromone traps for codling moths in apple trees

Place pheromone traps for codling moths in apple trees

The codling moth is responsible for the maggots in your apples. Place a pheromone trap in the trees in May. To a male codling moth, the trap smells like a female and they will be unable to resist. They are soon caught on the sticky part. You need to check the trap regularly to see if numbers are increasing, so you can tell if it will be necessary to spray them.

Watering and fertilising

Continue to water any recently planted young veg plants and start to use a liquid feed a couple of times a week on your tomatoes.

Thin directly sown veg

The rows of directly sown seeds should be sprouting in your veg patch. Thin them to an appropriate spacing before they get too congested and end up fighting for resources.

Gardening jobs: Ornamentals

Stake tall perennials

Stake tall perennials like Delphinium

It’s best to do any staking before it is actually needed. Use natural materials where possible and make sure the supports are already in place before the plants start to fall over. By tying them in as they grow the supports will quickly disappear into the border.

Harden off plants

Any tender annuals that have been grown in a greenhouse will need a few weeks of hardening off to acclimatise them to outside temperatures before planting them out.

Clip Laurel hedges

Clip Laurel hedges

To encourage lush and healthy growth, Laurel hedges are usually trimmed in late spring or early summer. Let them flower and start to put on new growth before trimming them into shape. Using a hedge trimmer can leave ragged edges, so it looks better if you cut it with shears ( if you have time!)

Plant out Dahlias

Plant out Dahlias

Dahlias are great for providing late-season colour in the garden and will flower until the first frosts. They should be gradually hardened off before planting them out at the end of the month. Give them plenty of feed and water to get them established and watch out for slugs as they can be devoured overnight.

Cut back early spring flowers

Cut back early spring flowers

Early spring flowering perennials like pulmonaria will have finished by now and may be starting to look a bit long in the tooth. Cutting them back to ground level will encourage them to put on a fresh flush of leaves which should stay looking good through the summer.

Remove forget-me-nots

Remove forget-me-nots

There is a reason they are called forget me nots. If you leave them in the bed they will set enormous amounts of seed and whilst they are a welcome addition to the early spring display, the seedlings can swamp out everything else if left unchecked. Yank them out as soon as flowering slows, they should have already set plenty of seed for next year.

Gardening jobs for the lawn

Regular cutting

Regular cutting

The lawn will start to grow rapidly this month, especially if you have just given it a dose of feed. Try to cut it once a week during the late spring and early summer. The green part is just the growing tip of the grass, and if you have to cut a lot off at a time it will appear brown and patchy. It’s much better to cut little and often.

Gardening jobs for the pond

Remove blanket weed

Remove blanket weed

As the water in the pond starts to warm the aquatic weeds will start to grow rapidly. Blanket weed is a filamentous green algae that will cling to the edges of the pond and rocks, quickly smothering the area. Twirl it around stick, and scoop out as much as you can with a net before applying aquatic quartz powder to the pond. This will remove the nutrients it is feeding on and should limit its spread.

Gardening jobs in the greenhouse

Open vents

Open vents

On a sunny day the temperature in a glasshouse can quickly become too much for many small plants. Watering early in the morning, opening the doors and windows and damping down paths will help to keep the temperature from getting too high during the day. The evenings can still be cool, so remember to close up again on a night.

Watering

The green house will be full of young plants ready to go out in the garden so it is essential to keep an eye on watering. Lifting pots should give an indication of how much water they currently have.

Gardening jobs: Pests and diseases

Slugs

Slugs

If we have a spell of showery weather, (which is more than likely in the UK) the Slugs and snails will be out in force looking for a meal. You can give your plants some protection by watering nematodes on to susceptible areas. These microscopic worms are parasites of slugs and will reduce the numbers enough to give your hostas a fighting chance.

Black spot on roses

Black spot

As much as we all love roses, the majority of varieties seem to have a propensity to come down with black spot. Removing affected leaves seems to reduce its spread, but ensuring your plants are healthy in early spring is often the best cure. Prune away any wood that shows lesions in the winter, remove all leaves from under the bushes and give them a feed with ash. The high potassium level will encourage healthy growth and flowers and it may also help to reduce the levels of fungal pathogens.

Gardening jobs: Pruning

Prune early spring flowering shrubs

Prune Early spring flowering shrubs

Shrubs like Chaenomeles, Ribes, Kerria and Spirea will flower early in the year. Once flowering is over it is the ideal time to prune them. They will flower next spring on the wood that grows this summer, so its a good time to consider how much they could grow over the next year so you won’t have to come back and trim them again.

Cut back Clematis Montana after flowering

Cut back Clematis Montana after flowering

Clematis Montana is a fabulous climber and in spring it will be covered with a dazzling display of creamy white or pink flowers. After flowering they will start into growth and can be quite rampant. To ensure they don’t get too big, trim back any growth whilst it is still soft and actively growing. They hate being cut back too hard and will often give up if you cut into older, woodier stems so just trim the tips to keep them well-behaved.