Kim Wilde answers your gardening questions.
I have a broom that's been in the ground for about 10 years and which I have never pruned. Now, it is about 5ft tall and only gets blossom at the top - underneath is a ragged woody mess. If I prune it hard to promote growth around the base for next year, will I kill it?
Brooms (Cytisus) are short-lived, lasting 10 years or so before they die or, as in your case, become unattractively leggy, especially on poorly drained soil such as clay. They flower on the previous year's growth and should be pruned immediately after flowering, as this prevents seeds forming, which weakens the plant. Cutting into old wood is not an option, as it would probably kill the shrub. I would take semi-ripe cuttings in late summer, by stripping off a young, vigorous shoot so that it peels away with a 'heel' of old bark attached to the base. Place in some pots with multipurpose compost mixed with sharp sand for drainage, water in, and protect from frost. Cuttings should root during winter and spring, ready for planting out in May.
Do you have any tips for growing gardenias in a pot in the house? I buy a sturdy looking one every year, and it always shrivels and dies. I've attempted to keep it in both sun and shade - still the same sad outcome.
Gardenias are known to be fussy plants, but their glossy evergreen leaves and deliciously scented flowers make them very popular, and obviously keep you coming back for more punishment. They like cool, well-lit rooms, and the compost always slightly moist but never waterlogged, as well as regular misting (though not on the blooms). Softening the water by boiling is good, too. They resent temperature change, and would have reacted badly to your location changes, although they would have benefited from feeding during the growing season. Check there are no heat vents, radiators or direct sun getting in through glass, as all of these might cause leaves to shrivel and die. Humidity might be the problem, so stand pots on trays of wet gravel to increase it.