Prune out frost damage from
affected evergreen shrubs.
Cut back tender shrubs such as
Penstemon, Caryopteris and
hardy Fuchsia after danger of
frosts has past.
Clip evergreen hedges. If not too woody, shredded clippings can be
added to the compost heap.
Prune spring-flowering shrubs such as
Berberis,
Chaenomeles,
Choisya and
Ribes after flowering. Remove one
stem in three from Kerria and
Spiraea ‘Arguta’, and shorten the
other flowered stems to a suitable sideshoot. Evergreens such as
Viburnum tinus can also still be
trimmed this month.
Prune overcrowded, dead or diseased stems of
Clematis montana once it has
finished flowering. Untangling the stems can be fiddly, but once you can
see where you are cutting, you need not worry about pruning this plant -
it will take even hard cutting back very well.
Late spring is a good time to coppice or pollard
Eucalyptus.
Tie in climbing and rambling roses as near to horizontal as possible.
This will restrict sap flow causing more side-shoots to grow along the
length of stem. Therefore more flowers will be produced.
Young mimosa trees (Acacia dealbata)
can also be cut back now. Mature trees respond less well to pruning.
Remove any reverted green shoots on hardy variegated evergreens, to
prevent reversion taking over.
Prune wall-trained pyracanthas, removing any shoots coming out from
the wall, and shortening other new growth to about 8cm (3in). This
encourages spur formation, and increased flowering relative to green
growth.
Ensure newly planted trees and shrubs do not dry out. Water with
rain, grey or recycled water wherever possible.
Loosen any tree ties that are digging into the bark, or could do so
soon as the trunk girth expands.
Twining climbers (such as honeysuckle and
Clematis) need regular tying in
and twining around their supports.
Take softwood cuttings of deciduous shrubs, including
Forsythia,
Fuchsia,
Hydrangea macrophylla,
Philadelphus and
Spiraea.
Layering is a good way to propagate climbers and lax-stemmed shrubs.
Layers should root by next spring, especially if attention to watering
is given during dry weather. Examples to try include
Philadelphus,
Forsythia,
Hydrangea and
Lonicera.
Pest & disease watch
Viburnum beetle grubs start nibbling holes in the leaves this month,
giving plants a tattered appearance. Inspect
V. tinus and
V. opulus regularly and spray or
pick off the grubs by hand.
Check roses for signs of blackspot, aphids and leaf-rolling sawfly
damage.
Inspect sick looking box and holly trees for signs of blight.
Phytophthora root rots can
cause die back on mature trees and shrubs. Wet winter weather followed
by a hot spring and summer can encourage this problem on susceptible
woody plants.
Check for damage or cankers on deciduous trees.
Caterpillars, aphids and other fly pests can all be problematic at
this time of year. Early infestations can be managed by hand removal,
but approved insecticides are necessary for more serious attacks.
Camellias sometimes fail to perform as well as hoped. This can be
down to insufficient watering in the previous summer or current spring,
but can be also be due to problems with frost, win, or poor soil
conditions. Try improving cultural conditions before concluding that the
problem is a pest, fungus, or virus.