May is the time to…

Remove blanketweed from ponds regularly

BOX HEDGING: Start clipping box (Buxus) hedging. This is an ongoing job through the summer months if you have as much as we do.

DAFFODILS: Remove leaves from daffodils as they turn brown and collapse. Later flowering varieties benefit from removal of the dead flowers (to prevent seeding and to focus plant on building up the bulb), the leaves should be left for six weeks after flowering to help build up the flowers for next year.

FROST ALERT: The last frost date is usually the third week in May, although take local growing conditions and the weather forecast into account. This means you can remove insulating material permanently from tree ferns and other tender plants.

LAWNS: Mow the lawn once a week unless the ground is very wet underfoot. Keep the edges neat to set off borders and for general tidiness. If you have a wild area, then use a garden trimmer.

PLANTING: Now is a key time for planting both hardy container plants and some of the tender plants, such as bedding plants and over-wintered dahlias.

PONDS: Check the level of ponds and water features, and top up with water if needed. Remove blanketweed regularly, taking care not to remove any pondlife at the same time.

PRUNING: Prune shrubs that have flowered in spring, for example, Exochorda, Berberis (evergreen types), Cytisus and Ribes. Trim early-flowering clematis after flowering if they have outgrown their space.

WET DAYS: Keep off lawns and soil when it is very wet; instead, prepare prunings for shredding (do not use a power shedder outside when it's wet), or top up paths and the base of trees with chipped bark or a mulch of your choice. Catch up with plant labels – particularly for investment plants such as trees and shrubs.

'Lollo Rosso' lettuce makes a colourful crop

ASPARAGUS: Despite its short cropping season, asparagus is a worthwhile and tasty crop. We grow plants in raised beds in the Elizabethan garden at Barnsdale.

HARVESTING: Harvest first early potatoes such as 'Swift'. Make a last harvest of leeks and endive. Once crops such as chard and kale have finished, dig them up and compost them. Also dig up overwintered spinach.

PLANTING: Plant out chard cabbage 'Hispi' and turnip 'Golden Ball', and lettuce of various types – for a colourful edging try 'Lollo Rosso'. Also plant out Brussels sprouts, cauliflower, pumpkins, French beans, peas, tagetes and runner beans. We have a parterre at Barnsdale Gardens and use it to plant out turnips, carrots, artichokes and lettuce.

SOWING: Direct sow crops such as French bean 'Masterpiece'. More unusual crops that you can sow direct into the ground include: salsify, scorzonera, rocket, spinach, radish and beetroot.

STAKING: Stake broad beans just in case they get knocked over by wind or heavy rain.

TIDYING: Tidy through your beds to keep your plot looking its best.

WEEDING: Weed areas where you are growing your own food or cut flowers; this is a regular job through the season. A long-handled, sharp hoe is ideal for traditional beds. When growing produce in raised beds or containers, try short-handled tools or hand weeding.

APHIDS: Spray soft soap on plants in greenhouses and conservatory to control aphids if present.

CONDITIONS: Check conditions in greenhouses and conservatories every day and adjust as necessary. Plants need regular watering but remember to ventilate when the weather is warm. Damping down floors in the morning helps to keep the environment cool and humid.

SOWING FLOWERS: We sow nasturtium varieties 'Alaska', 'Jewel of Africa' and 'Tutti Frutti Mix' into modules. These plants can be used to fill gaps in hot, dry beds later on. Sow flower seeds such as Mimulus 'Big Boy Orange', Scabiosa atropurpurea 'Summer Berries', Hibiscus 'Flamingo Mixed', Nolina 'Songbird Mixed', Salvia Roemeriana 'Hot Trumpets' and Linaria 'Little Sweeties Mixed' into trays.

SOWING VEG: We sow Brussels sprouts 'Red Delicious' and 'Cumulus'; broccoli 'Early Purple' and 'Claret'; and carrot 'Chantenay Red Cored' into modules.

It's easy to sow seeds in modular trays and you can also use these to grow on pricked-out seedlings, such as lettuce 'Lollo Rosso'. We also sow a few varieties of French bean into deep modules, or pots.

Pots 8cm (3in) wide are good for sowing sweetcorn (or re-use coffee cups from vending machines and put in drainage holes). These pots are also ideal for runner bean 'White Swan'; courgettes 'One Ball' and 'Defender'; peas 'Sugarbon'; and squashes 'Baby Bear', 'Butternut' and 'Cobnut'.

RUNNER BEANS: Now's the time we plant runner bean 'Celebration' into large containers.