More ideas on planning a perennial border are included in Claire Austin’s Book of Perennials, price Â£17 (including p&p). Mention Garden News when you order (tel: 01686 670342; www.claireaustin-hardyplants.co.uk) and you’ll receive a signed copy.
QWhat causes Brussel plants to only produce small sprouts? I added chicken manure pellets before planting, but they haven’t helped.
Roy Strange, Swindon
A Sprouts, like all brassicas, are hungry plants. They prefer friable, fertile soil that contains plenty of phosphorus, nitrogen and potassium. Chicken manure will boost mineral levels but if your soil’s not in good condition or poorly drained, the plants might not develop healthy roots.
Plants should also be spaced with at least 60cm (2ft) between each and 75cm (30in) between rows.
Give your current crop time to develop. If plants are tall, leafy and not overcrowded, those buttons should expand to a better size. And when they do, you could be harvesting long after Christmas.
Check roots are healthy, too. Poor root development can result from earlier attack by cabbage root fly, by club root or even soil compaction. If your soil is acidic and club root is present, grow the young plants on in 13cm (5in) pots next year. Plant them out when their roots are well developed, a little later in the year.