June gardening tips
Ensure trees or shrubs planted in the last couple of years on lawns or in areas of rough grass have a circle of clear earth around them – this must be kept clear or grass will prevent essential moisture getting through. Mulching with bark or compost will help.
Cut back tender shrubs such as penstemon and hardy fuchsias once frost is no longer a danger.
It’s Derby Day this month - the traditional day for clipping box. Trim other evergreen hedges too such as privet and lonicera.
Prune spring flowering shrubs such as Weigela, Philadelphus and Deutzia after they have flowered towards the end of the month - cut out some of the oldest wood (up to a third of the bush) right down to the base - don’t leave it too late or the new growth will not have enough time to produce a decent show for next year’s flowering... procrastination is hopeless here!
Keep spraying roses with fungicide to ward against black spot and mildew. Do this in the evening to avoid harming bees. Repeat every fortnight until the autumn. Remember that if an infection sets in, all the stricken leaves must be burnt - do not leave them on the compost heap as this will become the perfect incubation site. Feed with a foliar feed and beware greenfly - treat immediately if an infestation occurs - ask in the garden centre for advice as to what to use if you are unsure.
If you prefer large showy blooms, ‘disbud’ your hybrid teas - remove all the little buds to allow the king bud of each cluster to develop in glorious isolation.
Tie in climbing and rambling roses horizontally - this encourages more flower production as fewer side-shoots are produced due to restricted sap flow.
Prune Clematis montana hard once it has finished flowering. Other hard pruned clematis should now be growing vigorously - tie the new stems in regularly to prevent a haphazard tangle of new shoots which can break easily.
Other twining climbers such as honeysuckle also need constant attention for the same reason.