Pests in the greenhouse
As the new growth in your greenhouse becomes lush and thick pests and diseases may also be thriving. Constant vigilance is needed to detect the first signs of greenfly, blackfly or whitefly. Aphids are best squashed by hand at first sight. However if infestations become large regular spraying with a proprietary insecticide will become necessary. The alternative is to introduce other insects which feed on the eggs or lava of these pests. This natural or organic approach to pest control is more expensive and only likely to work as a preventative measure before a full infestation has taken place.
More serious still, and usually in very dry hot period, red spider mite comes into play. It usually favours older more mature plants with dead leaf material and often those with hairy leaves (e.g. Abutilon). The first thing you will notice is tiny spiders webs covering the leaves. You will need to look much closer to see the tiny red spiders themselves. Regular spraying is essential once an outbreak occurs but, better still, put the plant outside for a spell as cooler conditions are not appreciated by red spider mites and they cannot colonise your other plants.
Climbers
Check that your climbers are trained in properly to the wires or trellis which are there to support them. Prune or add more support to avoid the new growth collapsing in on itself.
Leptospermums
Leptospermums will be at their flowering peak now. Consider potting them on after flowering and keeping them outside as patio plants for future summers. How to care for shrubs
Rare plants
Try a new, rare and unusual climber or two in your greenhouse.