Advice for potted spring bulbs
QI have a large number of spring bulbs in pots, which I want to keep in situ. Apart from putting them aside after flowering once the foliage has died down, is there a particular feed that they would benefit from?
Marion May, via email
ABulbs are pretty good at feeding themselves so long as the leaves are kept healthy for the rest of their natural life.
However, they might benefit from liquid feeding with a general-purpose fertiliser every two weeks, or top dressing with a granular slow-release or controlled-release fertiliser with a balance of major and minor nutrients designed for general plant health throughout the year. Suitable products include Miracle Gro, Vitax, Phostrogen All Purpose, Gro-Sure All-Purpose – and lots more.
Some bulbs, such as tulips and hyacinths, do better if lifted and then stored dry, ready for re-planting next autumn. Also, make sure that snails don’t bury into the pots and eat the bulbs.
This is really only a danger for surface-growing bulbs such as hyacinths, but mice and squirrels will dig up tulips and crocuses! Q
What are these caterpillars – are they friend or foe?
AMrs Townsend, Wisbech, Cambs
Concerned about caterpillars
These are the larvae of the swift or ghost moth. They live in the soil and feed on roots, tubers, corms, bulbs and rhizomes.
Adult moths fly from June to August and hover over beds and borders, releasing eggs in flight. These fall to the ground and hatch, and the caterpillars burrow into the soil.
They pupate the following spring or feed for another year.
There is no insecticide against them, so fork over infested patches so birds can get to the grubs.