My pear tree, which is planted in my lawn, has never done very well. What can I do to pep it up?

First, check that the lawn does not grow right up to the trunk. Grass will take food and water from the tree and affect its growth rate.

There should be a circle of bare earth about 1 metre in diameter at the base of the tree until it becomes established, after this you may grass right up to the trunk if the tree is growing strongly. Always feed and water a young or semi-mature tree regularly in summer.

Add Phostrogen to the water once a week to give a quick-acting feed, and fertilizer with a dry feed such as Vitax Q4 each spring for slow-release fertilising.

I love asparagus, but I have no vegetable garden. Is there another way to grow my own?

Certainly! Asparagus can be grown quite successfully in a flower border. Buy 1 or 2 year-old crowns of a dependable variety such as F1 Franklim in spring and plant them in a block 15cm deep, 30cm apart, in a deeply dug, well manured space in the border. 

Keep them well watered and regularly fed with a balanced liquid feed such as Phostrogen, but do not cut any spears the first year. Uncut asparagus will produce handsome, ferny foliage which looks most attractive in an ornamental border. The following year, you can cut one or two spears, and the third season you should be able to pick a good amount. 

Do not cut the spears after mid-July so the plants can recover, and always leave some earlier spears uncut so they will look decorative.   Asparagus fern can be used in flower arrangements providing you do not pick too much at a time. It should be cut down in autumn or early winter.

Why is my new escallonia hedge turning yellow?

On very limey soil, the young plants my find it difficult to access magnesium in the soil, and this is the usual reason why many young specimens turn yellow. Water with magnesium sulphate (Epsom salts) as soon as noticed, and feed more heavily in spring and mid-summer with a magnesium-rich fertiliser – a specific rose food is ideal.

Why are some of the leaves of my newly repotted aspidistra turning brown and papery?

These leaves have died, and it may be that they were already starting to die before you repotted the plant, particularly if it was very pot-bound. You may find the problem stops once the aspidistra has settled down, but if it continues, it may be that you have repotted the plant into too large a container and the roots are dying because the compost is too wet. If so, allow to dry out and water carefully until a lot of new leaves start to appear. Remember that repotting of houseplants should only be done when they are in active growth, between mid-April and mid-August.

Why are my cacti changing colour and going soft at the bottom?

Over-watering is the most likely cause. Cacti should always be grown in a free-draining compost in a pot with drainage holes in the base. If the pot is in an outer one, stand it on pea shingle so the water does not reach the drainage holes. It is unlikely your cacti will recover once the roots and base have started to rot in this way.

When do I prune a winter-flowering viburnum?

The best time is immediately after flowering, so it will make new flowering growths before next winter. They do not need to be pruned as a matter of course, only if the bushes are becoming untidy and woody, and pruning should be confined to removing a proportion of the oldest branches right down at the base. A very tired shrub may be rejuvenated by cutting hard back, but it may take two years for it to flower well again.

What fruit are suitable for growing in pots?

All fruit can be grown successfully in pots, providing the container is large enough and you use John Innes No 3 compost. It is not necessary to choose very dwarf forms, as the constraints of pot cultivation will ensure the plants do not get too large. Remember to feed and water regularly throughout the summer for good fruit production.