Final preparation for Summer

Flowers

• Plant summer bedding
• Prune spring-flowering shrubs to prevent them from becoming overgrown
• Finish sowing hardy annuals: the later they are sown, the later they will flower
• Put support frames into herbaceous borders to support plants with a floppy habit i.e., Lupins 
• Dig up, divide and replant polyanthus after they have flowered, discard any with disease 
• Start to harden off bedding plants by putting them out for the day and back in for the night 
• Protect susceptible plants from slugs 
• Clear out spring bedding from beds and borders when it fades, and fork in fertiliser 
• Plant hanging baskets and put them in the greenhouse until the risk of frost is gone 
• Watch out for pest and disease on all plants 
• Deadhead spring bulbs (but do not cut the foliage back yet) 
• Ensure newly planted plants are kept watered in dry spells 
• Prune spring-flowering shrubs to prevent them from becoming overgrown

Fruit 

• Mulch around Strawberries to prevent the fruit being spoiled, use straw or black polythene 
• Destroy any leaves of Peach and Nectarine which show signs of leaf curl 
• Spray a systemic fungicide on Gooseberries if mildew is a problem 
• Water newly planted fruit trees and bushes in dry spells 
• Harvest any early Rhubarb
  

Vegetables 

• It is possible to plant out Brassicas (cauliflower/cabbage) if they have been grown in a greenhouse. Remember to use a Brassica collar to keep cabbage root fly away 
• Most vegetable crops can be sown but delay if the soil is cold and wet 
• Plant main crop potatoes 
• Earth up early crop potatoes 
• Weed between any vegetable crops that are growing 
• Harvest any Asparagus spears that are showing

Lawns 

• Apply a weedkiller and fertiliser combination 
• Seed new lawns and cover to keep birds away 
• Mow lawns once a week if needed. Avoid cutting if there is frost on the grass 
• It is now a suitable time to spot treat lawns if no general lawn weedkiller is used 
• Lay new turf and keep well watered if a dry spell ensues

Greenhouse 

• Tie in the lengthening growths of Vines 
• Ventilate well and damp down on sunny days as long as seed are not being raised 
• Continue pricking out half hardy and tender seedlings 
• In a heated greenhouse remove side shoots from tomatoes, but not bush varieties 
• Pinch out side shoots of melons and cucumbers when two side shoots have been formed 
• Watch for pests and treat immediately using either a chemical spray or a biological control 
• Ensure heating is still available in case of a cold night

Ponds 

• Plant up new aquatic baskets with Water Lilies and oxygenating plants 
• Feed fish if they are near the surface 
• Keep pumps and filters running constantly

General Tasks 

• Control slugs and snails by trapping 
• Visit the garden centre for new pots and basket plants 
• Watch out for late frosts and keep fleece handy 
• Check watering each day as temperatures rise 

Plants which are at their best in May 
Aquilegia
(Granny's Bonnet) Syringa vulgaris cultivars (Lilac)  
Ornamental Cherries Crataegus (Hawthorn)  
Clematis Macropetela
(Clematis) Meconopsis betonicifolia
(Himalayan Blue Poppy) 
Centaurea Montana
(Perennial Cornflower)
Berberis stenophylla (Barberry) 
Dodecatheon Meadia
(Shooting Stars)  
Primula Veris (Cowslip)
Chimonanthus Praecox (Winter Sweet)   
Salix Caprea Kilmarnock (Kilmarnock Willow) 
Daphne Mezereum    
Forsythia (Golden Bells)