Q I never know what to do the poinsettia plant my aunt gives me every Christmas. It's starting to look sad and wilted now... and I have to admit, they usually end up in the bin.

A Unfortunately, by the time a poinsettia starts to wilt and drop leaves there's not a great deal that you can do to save it. They need warm conditions all the time, so should never be placed in a cool, draughty room. For those that have a plant that is still thriving and want to keep it growing put it in a warm, light room and never allow the compost to dry out. In spring start feeding weekly with a houseplant fertiliser and trim back the shoots by half to encourage new shoots and a bushy plant. Be careful when pruning, as the white sap in the stems can irritate the skin. It's a bit of fun keeping a poinsettia from one year to another, but to guarantee a healthy, red plant for next Christmas it is easier to buy a new one!


Q How late can you plant bulbs outside for spring flowering?

A Daffodils, crocus and snowdrops should be planted in September and October, and tulips are best planted in November and December. However, if you bought bulbs in autumn that you haven't got round to planting yet, get them planted as soon as possible – they'll never flower in a paper bag! There will be some losses, but the majority should grow, although they probably won't produce much of a display in their first year. To build the bulbs up for next year, feed the growing bulbs in spring with a general fertiliser such as blood, fish and bone, and allow the foliage to die down naturally.


Q When should you prune a Viburnum tinus, which is flowering now but getting huge?

A Viburnum tinus (Laurustinus) is a great garden shrub because it is evergreen, totally hardy and flowers for many months of the year. As it's such a tough plant, you can prune it fairly hard and into old wood. I would do this in spring when the worst of the winter weather is over. This way you get the benefit of the spring flowers and, because the weather is starting to warm up, new growth will soon start to grow.


Q I've got a small olive tree, bought this last summer, which I keep in a terracotta pot in a sheltered courtyard garden. Will it survive the winter if I leave it where it is, or should I bring it indoors? Also, should I be watering it? Despite rain and snow, it does look a little dry. I'm in the same quandary with two small potted salix (willow) trees.

A Olives are remarkably hardy, considering they come from the Mediterranean region. They will withstand temperatures down to minus 5C, but what they don't like is wet weather. As your olive is in a sheltered courtyard it should be fine, especially if you stand it close to a south-facing wall. In very frosty weather, it may be worth wrapping some old sacking or bubble polythene around the pot to protect the roots from freezing, and maybe drape some garden fleece over the top of the plant. It shouldn't need much watering through the winter months, but never allow the compost to dry out completely. Salix trees are hardy and will be fine left outside through the winter. They are much more tolerant of damp conditions.


Q Is there some fail-safe natural method of getting rid of clover from a lawn? We have small children and pets,
so I'm not keen on using chemicals.

A Controlling clover in lawns is difficult and even if you use
a selective lawn weed killer in spring and summer, clover can be hard to kill. Clover is however beneficial to the garden because it fixes nitrogen from the atmosphere and stores it in small root nodules to provide free and natural fertiliser for the lawn. For that reason I don't mind a bit of clover in my lawns.

Q I've just moved into a 6th floor city centre flat with a large balcony, which is pretty badly lashed by wind and rain. I'd like to grow herbs for cooking, particularly coriander, but will this be possible?

A All herbs grow best in full sun. So as long as your balcony isn't in full shade you will be able to grow a wide range of herbs. Annual herbs such as coriander, basil and dill are grown from seed every year. I would sow the seed in late spring in small pots on a sunny windowsill and when the plants are a few inches tall plant them into larger pots on the balcony. Other herbs such as sage, rosemary, thyme and mint are hardy and can be grown outside on the balcony all year round.


Q We've just moved to a new house and in the garden there is a pond with several fish in it. Do I need to carry on feeding them throughout the winter?

A Generally speaking, it is not necessary to feed fish through the coldest winter months when they are less active. In my pond the fish disappear at this time of the year to the bottom of the pond and I rarely see them. When they become more active in early spring, as the water gradually warms up, I feed them a wheatgerm fish food which is easy to digest, and by late spring change to normal fish food. I also use the wheatgerm food (which you can buy in garden or aquatic centres) in autumn as the fish activity starts to slow down.


Q Last year, our potatoes were destroyed by blight. Does this mean we can't grow them in our garden again this year?

APotato blight is a fungal disease that is air-borne and attacks potatoes and tomatoes when the weather is warm and humid. Last summer was very wet, which created the perfect conditions for blight spores to germinate on the plant leaves, resulting in dead plants. As long as you have cleared away the dead remains of your potato plants you can certainly plant more potatoes in your garden this spring. If we get a decent summer this year with more dry, weather, blight is not likely to be as much of a problem. You can also spray with a fungicide if blight warnings are forecast.


Q My tarmac drive and concrete path at the front of the house are in shade and get very mossy. How can I kill the moss and green slime?

A At this time of the year, moss and green algae on paths, drives and patios can make the surface very slippery. A power washer can be used to remove moss and algae, but be careful on old tarmac as the jet of water can loosen the surface. Liquid path cleaners and moss killers based on fatty acids are available and when applied they kill the moss and algae in a matter of days. However, these are only a temporary solution and the moss will grow back.


Q Strawberries are my favourite summer fruit and I would love to try and grow some. The problem is I don't have any soil to plant into, as my small sunny garden is totally paved.

A Strawberries grow really well in containers of all shapes and sizes such as window boxes, hanging baskets and patio pots. In early spring you will find small potted strawberry plants for sale in garden centres that can be moved into a larger container using multipurpose compost. Once planted, keep the containers in a sunny position and the compost moist at all times. When the plants start to flower in May, start to feed once a week with a high potash liquid feed such as tomato fertiliser or Phostrogen, and by mid-summer you'll be picking fresh juicy strawberries.

Martin Fish has worked in horticulture for 30 years. He started his gardening career as an apprentice and now writes for several gardening publications and broadcasts for regional BBC radio and TV. For the past three years Martin has been president of the North of England Horticultural Society (NEHS) – organiser of the Harrogate Flower Shows – and later this year will take over the position of show director. The Harrogate Spring Flower Show takes place from April 23-26 at the Great Yorkshire Showground. The NEHS started hosting flower shows in 1911, and the two Harrogate Flower Shows (in April and September) are renowned as two of the top gardening events in the UK, attracting top-class exhibitors from across the country. The Spring Show attracts approximately 58,000 visitors, making it one of the most important and successful shows in Britain.

Book for this year's Harrogate Spring Flower show before noon on April 14 and save £2 per ticket. Hotline 0870 758 3333 or www.flowershow.org.uk

Tomorrow: Health and fitness expert Miles Halstead answers your queries.