Your Garden in May
By John Dunster
As I am writing this we are having our first rainfall since late March. The succession of frosts in April has caused a certain amount of damage to some plants that had responded to the warmer weather earlier by putting on new growth. Camelias and Magnolias have been especially beautiful this year, but were, unfortunately, scorched by the frost and many did not recover. It was also a reminder to us not to cut off the seed heads from Hydrangeas too early as they offer the developing flowering shoots protection from the frost. There has been one bonus however, because of the colder spell, spring bulbs have stayed in bloom much longer that usual.
To maintain the shape and promote new growth lower down now is the time to prune spring flowering shrubs after they have finished flowering. Spirea once it has finished flowering cut the tallest, oldest shoots to the base. Forsythia is a vigorous shrrub and can soon become unmanageable. Simply prune after the last flowers have faded, cutting out the oldest flowered stems aeach year to encourage strong new shoots from the base. Other spring flowering shrubs that can be treated this way are Deutzia, Flowering Currant, Philadelphus and Weigela
Keep an eye on any shoots that may need tying in to their supports. Clematis Montana which are in bloom at the moment should be pruned when the flowers have faded as next years flowers will be formed on growth produced this year. These can be reduced by up to half or alternatively remove one in three stems down to 6-9in. Always water after pruning.
Prune Lilac when the flowers are over by removing 20% of growth, start by cutting back all the spent blossoms, remove any crossing branches and suckers from the base.
In summer. Sunlight shining into the greenhouse can create a dramatic build up of heat. Shading will help to keep the temperature down, this can be done in various ways. Integral blinds are most efficient but can be very costly, shade netting is an alternative but shade paint is the cheapest form of shading and works well.
Pants in pots need more attention than those in borders particularly for watering and feeding. Use a deep pot and choose a loam based compost making wure you can get to the container easily for watering each day and feeding once a week.
Now is the time to stake and support plants before they need rescuing, when they never really fully recover. So it is important to check your borders from Mid- May and put in supports for all the plants that will need it over the coming weeks and months. Various metal supports are available as well as using canes (which may become unsightly) or hazel twigs.
Bulbs in Containers
If you wish to save bulbs that have been grown in containers for next year, keep the foliage watered and feed with a liquid fertiliser. When the foliage has died down tip them out, dry them off and store them for replanting again in the autumn. It is also important to label them.
By early May the soil should be warm enough to make sowings of beetroot, radish, carrots and parsnips. Runner beans and dwarf beans can be planted outdoors by the middle of the month otherwise they can be grown indoors for planting out later in the month hopefully after any late frost. On warm dry days keep on top of the weeding using a dutch hoe, cutting off weed seedlings just below the surface. Keep rhubarb well watered to prolong cropping.