Thorny problems: how can I make my apple tree bear fruit? Bay watch I have bay trees in the garden that were here when we moved in. My neighbour tells me they are not the sort that you can use for cooking. Is there more than one type of bay tree? Anne Bird, Hayling Island I feel certain that you must have done the obvious thing: namely picked a couple of leaves from your bay tree, crushed and sniffed them. If they smell right, they are right. There are only two varieties of culinarily-useful bay. The one with which we are most familiar, Laurus nobilis, is often referred to as bay laurel and frequently grown as a rather frost-vulnerable "lollipop." It is hardier if grown in the ground and not lollipopped, incidentally. There is another, less well-known variety, Laurus nobilis 'Angustifolia" (willow-leafed bay). As the name suggests, this has skinnier (but still aromatic) leaves. Laurus nobilis, a native of the Canary Islands, is the "laurel" historically sacred to the god Apollo; from which we get the expression "resting on our laurels" etc. Long before it was used to flavour food it was associated with good luck and with warding off evil spirits and even the plague. Could that be how a couple of potted bay trees became such familiar entrance sentinels? I can see how confusion could arise. The leaves of unrelated Portugal laurel (Prunus lusitanica) are superficially similar to those of bay laurel, but if scrunched they are completely odourless and no use in cooking. Furthermore, we often lazily refer to the somewhat ubiquitous shiny-leafed fast-growing hedging plant Prunus laurocerasus as "laurel." Anyway, Anne, scrunch away. I am sure the truth about your trees will out. I might add that several bay laurel trees in one garden (unless indeed they are tidy potted sentinels) might be several too many. Un-pruned they do have prettily scented flowers, but they also can become huge, rather dull and light-blocking trees. Heaven scent advice? I suppose it was to be expected. My enthusiastic piece about a clutch of useful evergreens to both brighten winter gardens and tickle the olfactory senses resulted in a flurry of emails from gardeners experiencing problems relating to three of them. First in line is Sheila Kenyon from Hampshire, who has been growing Daphne odora 'Aureomarginata" in her garden for the past three years, expecting delicious February scent. She is still waiting. Her daughter, who lives locally, has a 10-year-old specimen that is equally shy to flower. Both shrubs receive a few hours of sun a day (is that just in summer, I wonder?) and are planted in chalk soil that is improved with compost. Somehow I don't think it is about the chalky (limy) soil. Daphnes are not as fussy about soil pH as you might imagine. It could be a lack of direct sun from autumn to spring: plants grown in sunnier sites seem to flower rather better than those growing in winter gloom. It could also be that they are being fed too much by their anxious owners, particularly with nitrogen-rich fertilisers. If these were my daphnes, I would be meaner to them - just give them sulphate of potash (which encourages the production of flowers) twice a year, in spring and late summer/early autumn. Next came Freda Carr, whose beautiful but portly pittosporum is encroaching on her path and is also far too tall. If she cuts it right back will it re-sprout from old wood, she asks? As these lovely beasts get bigger they naturally start to become more treelike. So I fear that while the vigorous top can safely be lopped away and will send up a lot of new growth almost immediately, if pruned similarly hard the bottom branches may just give up. The answer is that pittosporums should be trimmed and shaped little and often from relative infancy. From May to July, when they are growing, is the right time to mess with them, not now. Janet Bingham feels cheated, never having noticed any scent from her pittosporum. I find their sweet lily-of-the-valley whiff is most noticeable in the evening, on plants grown against warm sunny walls. Flowers are produced in early summer. They are tiny, colourless and tucked in among the leaves, and followed by little nutty seeds. Another spring shrub, famous for its strong scent, is sarcococca, which continues to disappoint Jill Hume in Lamberhurst. Initially grown unsuccessfully in a pot and now even more unsuccessfully in a prime sunny spot in the ground, she can't decide what to do with it next. Sarcococcas are serious candidates for areas of poor soil and deep shade. If I were Jill I would dig it up in the next few weeks and move it to somewhere more horrid (it is not a good-looker for most of the year anyway). My own patch of sarcococca grows alongside a scruffy path between garage and back door, so at least I catch its January scent as I pass. Flowering on the previous year's growth, the plants benefit from a trim in late spring. In Jill's case that will mean the removal of about 10cm/4in of growth that should have flowered - but didn't.