Danny Calderbank has some top tips for May, answers your garden queries and serves up a few horticultural hints and wrinkles.

Beginning in mid April and running for at least six weeks is one of the best free spectacles imaginable. I refer of course not to some TV or film show but to the marvel of flowering trees and shrubs. For many it is the best time of year and I cannot argue with that sentiment for there is warmth and a feel-good factor that for adults, can even outshine Christmas! The only people who might not enjoy it so much are sufferers of early hay fever and although it’s no consolation, the likely cause is birch pollen.

Some blossoms are more ‘showy’ than others although I prefer the smaller, single petal flowers in white or very pale pink. However the prominent double flowers in red and stronger pinks are, naturally, more obvious; at least they are until a high wind causes these larger flowers to fall like confetti. Last year in my locality the fall of flowers was more the result of a cloudburst from which the rain-sodden petals never recovered. We have come to expect such a display will be short-lived but any longer and it might not be so captivating!

The most popular trees are the flowering cherries (Prunus) that can include almond, plum and peach while flowering crab (Malus) should not be overlooked and also hawthorn, particularly the double red ‘Paul’s Scarlet’. At this time of year your local garden centre will have trees in flower for you to select; alternatively order a bare rooted plant from a nursery for collection during winter.

As with all trees dig the hole a little larger and deeper than the container or root ball; loosen the soil at the base and position the tree so that the soil mark on the stem is level with the adjacent ground. Position a tree stake taking care not to damage any roots and apply water to soak the area before replacing the rest of the soil. At this point I like to add a generous amount of bone meal to the soil being returned; this inexpensive and readily available fertiliser slowly releases nutrients to the roots ensuring that growth is not inhibited.

While trees are wonderful do avoid the temptation to plant close to a boundary; your two metre tall tree will soon be five times that size and it is unfair to expect your neighbour to have half the roots and branches! Should you not have room for a tree then plant shrubs instead as a little thought now can avoid problems later. Finally, if you are planting in a lawn then keep a circle of at least one metre diameter around the tree free from grass. This will ensure the tree roots are not in competition with the grass for adequate water and avoid a slow growing and stunted tree. Water frequently during the first year and also in drought conditions for a healthy, strong tree that will provide flowers for generations to come.


QUESTIONS AND ANSWERS

Last year our lilac bush didn’t flower and to be brutally honest it’s not a nice enough shrub to keep unless it flowers. Do you have any suggestions?

I totally agree with your sentiments and would not personally select this shrub but in some gardens it earns its keep by providing a windbreak or screening an area for privacy. Unfortunately, lilacs are also unreliable and for no apparent reason will fail to flower although they do prefer alkaline conditions and this might account for their lack of reliability if planted elsewhere.

However, the lilac family is a large group and there are a few gems among them to consider purchasing. The dwarf Syringa microphylla ‘superba’ or Syringa meyeri ‘Palibin’ only grow to a modest height and have delightful flowers in the range pink/mauve.

I love the blue flowering Ceanothus. Can you recommend a variety suitable for a position that is far from sheltered?

This family extends to over 100 varieties and species covering both the evergreen and deciduous forms. A really tough one is ‘Autumnal Blue’ that flowers in profusion for many weeks although perhaps not so prolific as the spring varieties. Ceanothus is not a long-lived shrub but by trimming them annually to maintain shape they will also remain more youthful.

The surface of our garden pond is covered with duckweed and where we once looked into clear water and observed our fish we now cannot see anything other than this plant.  Is there a remedy?

Sooner or later duckweed will arrive, usually as a result of a visit by a heron or duck that has some of these tiny plants attached to their legs or feathers. It spreads rapidly and while each plant is small the resulting colony can cover large stretches of water denying light with the consequent loss of submerged aquatics. Unfortunately removing the weed with a net is the only method of control available but it does work well when done regularly and will prevent the weed becoming a problem in the first place.

CUTTINGS

Sow Nicotiana suaveolens as soon as possible for a late summer display. This variety is a shorter form than N. sylvestris and is much more suitable for the smaller garden. The tubular blooms nod gracefully on slender stems and will fill the air with a sweet fragrance particularly in the evening. It is available from Thompson and Morgan (01473 68821)

Sweet peas can still be sown directly where they are to flower. It is certainly not the best way but if you want sweet peas now it is the only option. Train the shoots up netting, wire or sticks for an instant and attractive screen. Not all are scented but try Suttons ‘Juanita’, a heritage mixture with small to medium flowers that is!

As fast as you read this, yet another weed has germinated in your garden. That’s just the way it is and while there are numerous courses of action to take at this time of year, I would recommend hand weeding or hoeing.

There is still time to sow some annuals that will flower this year. Try fragrant night -scented stocks, white flowered cosmos and Oenothera odorata (evening primroses) that open their brilliant lemon flowers at dusk and are also attractive to moths

In small spaces less vigorous clematis such as C. alpina and C. macropetalata are a better choice. The good news is that they don’t need regular pruning but will benefit from the removal of spent flowers as soon as flowering is over.