I have about 30 Nerine bulbs planted in my garden which are very old and some which are newer. This year only two bulbs have produced a flower and the rest have green leaves coming through so won't flower. What can I do to encourage more bulbs to produce flowers? 

• Overcrowding reduces flowering in Nerines.
• Lift your bulbs, split up the clumps and replant. Do this every 3-5 years after flowering has finished or when the bulbs have died down and gone dormant.
• Feed your bulbs in late summer, early autumn when green shoots start appearing, use a balanced bulb fertiliser such as Tui Bulb Food, this will help promote flowering, re-apply bulb food when bulbs have finished flowering in autumn.