Readers question: Marjorie, from Guisborough, has a holly tree in her garden that has never produced berries despite flowering.

She wonders why this might be, and would like to know if, apart from Christmas decorations, holly has any other uses.

THERE are about 400 species of holly. It is sometimes deciduous, but mostly evergreen trees and shrubs, with often angled shoots and alternating leaves. It can be grown as a bushy shrub or small specimen tree. Its dense, slow-growing habit makes it suitable for topiary training and it can also be used as a windbreak and burglar deterrent.

The colour of the berries varies from red to scarlet, black and yellow, but unless you have a self-pollinating variety, you need to plant both male and female plants. The principal type of holly grown in this country goes under the botanical name of ilex aquifolium, meaning needle leaf. Be careful, though, as the cultivar names aren’t always indicative of the plant’s sex. Ilex aquifolium Silver Queen is a male plant, for example, while Golden King is female. Both males and females have white flowers, but only females have berries. There are two main self pollinators, namely ilex aquifolium JC van Tol and ilex aquifolium Pyramdalis.

If the plant produces few or no berries, it’s probably because it is male or it could be a female plant that hasn’t been pollinated. A poor show of berries could also be due to cold winds and wet periods during flowering, which deter insects from pollinating the plants.

Occasionally, hollies may suffer from root rot. If this happens, remove the plant, burn it and disinfect the soil.

The use of holly as a symbolic winter decoration, with its shiny, prickly leaves and blood-red berries, goes back to the Celtic peoples of northern Europe, who decorated their homes with it during the time of the winter solstice, or Yule.

The ancient Romans believed that holly warded off lightning strikes and witchcraft and sent boughs of it to friends during the winter solstice. The early Celtic Christians associated the prickly holly leaves with the crown of thorns from the crucifixion and the red berries with the blood of Christ.

In South America, holly is used in making matte, a type of tea. The wood of the holly tree is used in the manufacture of pianos keys and chess pieces, as it has a fine grain. Medicinal extracts have been used for centuries in traditional remedies for dizziness, hypertension and even cancer.

Jobs this week

Cover alpines that might rot in the winter wet with a firmly propped-up pane of glass that allows free passage of air.

Plant rhubarb in well-manured ground and cover established plants intended for forcing with a rhubarb pot or lightproof bucket.

Strawberries will benefit from a protective mulch. If you haven’t done it already, mulch plants now with straw.

■ Brigid presents the BBC Tees Gardening show on Sundays from 1pm to 2pm. Questions can be answered on the day by emailing brigidpress@bbc.co.uk anytime during the week, texting 07786-200995 or phoning 01642-225511 during the show. Written letters can be addressed to Lazy Dayz, 10 Farm Road, Houghall, Durham, DH1 3SF