ASK MONTY

QHow many years can agapanthus stay in the same pot and can you split them? Josie Heayns, Berkshire

ATraditionally, you only repot agapanthus when they break the container – meaning they do well with very constricted roots. If you do repot, do not give them more than an inch or two of extra soil around the edge of the pot. They do best on poor or stony soil. Split them in spring.

QCan I plant a crab apple tree in the exact same spot a sambucus [elder] has been growing for years? Graham Barks, Staffordshire

QMy bumper crop of tomatoes is not getting ripe. What can I do to help them redden?

Eric Hughes, Greater Manchester

AAI don’t see why not. As long as the elder was healthy and you dig out most of the roots then there should be no problem at all.

The warmer a tomato is, the quicker it will ripen. Sunlight tends just to harden the skin, so put them in a warm drawer and many will ripen in the dark. Add a ripe banana and that will speed the process up. Also, hanging the entire plant upside down from a beam in a shed or garage will help with ripening and improve taste. Finally, you can always make green chutney and green tomato soup.

Write to Monty Don at Weekend, Daily Mail, 2 Derry Street, London W8 5TT or email monty.don@dailymail.co.uk. Please include your full name and address. We regret Monty can’t reply to letters personally.