Letters

Q: I used to have a long thin trowel that was ideal for putting in bedding plants. Are they still available today? — G. Bayliss, Fort William

A: They certainly are. The Dutch firm Sneeboer make a real beauty in stainless steel. It sells at £19.70 from Harrod Horticultural (01502 505300; www.harrodhorticultural.com).

Q: My best present last Christmas was a tree fern. It has done well but now it needs winter protection. Do I cut off the fronds, and if so how far back? With what do I wrap the trunk, and should I leave the top open? — J. Edwards, West Malling

A: Tree ferns are naturally evergreen, so do not cut the fronds. If frost blackens them, bend them down or tie them over the crown as insulation, then cut them off in spring. The first and best protection you can offer is a sheltered position out of the wind; remember these are plants of woodland glades. Then drop a handful of dead leaves into the crown to keep the frost off the live bud, which is at the top of the trunk. Thereafter, in the face of a seriously cold winter or northern climates, erect a cylinder of chicken wire or rigid plastic mesh around the trunk (something porous, not plastic) and fill it with straw or hedge clippings — anything to provide some insulation.

Q: I garden on clay soil and like to grow delphiniums, lupins, etc. They never last more than one season, which I put down to the small black slugs constantly lurking in the soil. Someone advised me to sprinkle aluminium sulphate on the soil, just before rain in November or December, and again in March-April, to solve the problem. Where can I find the stuff? — R. Curtis, Epsom

A: Aluminium sulphate is produced by Growing Success, and sold by the Organic Gardening Catalogue. It works by contact with slugs and their eggs, and with minimum risk to other wildlife and pets. The timings you write would kill the eggs in the soil and protect the resting crown buds, but you could usefully continue applications into May and June, applying after rain (it is soluble and easily washed through) to deal with slugs on the surface. It is of course not the panacea everyone hopes for, but every little helps. Nor is it strictly organic, but at least it is environmentally friendly. (0845-130 1304; www.OrganicCatalogue.com).

stephen.anderton@thetimes.co.uk

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