Tony Dickerson answers your questions
Q
Why am I having so many problems with the leaves and flowers on my containergrown camellia? Karen Nu all, by email
A
Fortunately, they’re among the easiest of shrubs to grow in pots but you need to follow some golden rules. First, from spring to autumn, they must be kept well-watered and, even over winter, they should never be bone-dry. It’s particularly important to keep them watered in August and September when the new flower buds are formed. If they go dry, buds will either fail to develop, fall off during frosts over winter or fall off the shrub in spring. Positioning is also very important. Container-grown camellias want a sheltered spot out of direct sunshine. In exposed situations over winter leaves may become damaged and brown at the edges, especially if the shrubs dry out. In summer, hot, bright conditions will lead to high temperature injury to leaves, where the sun will scorch foliage. Again, this will be more pronounced if plants dry out. I think this is the main cause of the brown leaves on your camellia. Ideally, move it into shade and up the watering. The worst affected leaves can simply be pruned off. Continue liquid feeding with an ericaceous fertiliser every fortnight, until the end of August. Each year, scrape away 2.5cm (1in) of the potting compost and replace with fresh, adding some controlled-release fertiliser for ericaceous plants. This can be done in autumn or spring, as time allows.
Every few years you need to do a repot. This is best done in late September or early October. Remove the shrub from its container and, using an old saw, take about 5cm (2in) off the base of the rootball and three or four slivers down the side. This will allow you to get in with a sharpened piece of stick or similar and tease the roots well out, which by this time will be very matted. Any particularly long roots can be pruned off.
Place fresh potting compost in the bottom of the pot to ensure the top of the rootball is at its original height and fill in round the side. Overlong branches can be shortened immediately after flowering in spring.