Beacons in 
the gloom

Outdoors, the hardiest of plants battle on, some even managing to produce blooms.

But it’s indoors where the flowers 
make their mark, and pelargoniums are among the stars, probably because they find it difficult not to bloom whatever treatment they receive, so they are favourites with the easy-going gardener.

Even those plants which have grown outdoors throughout summer and into autumn and should, by rights, be given a welcome rest or even discarded to the compost bin, can be persuaded to continue blooming if they are brought into the house and re-potted.

In a container, in well-drained soil-less multipurpose compost or soil-based compost such as John Innes No 2, they should thrive.

In ordinary garden soil, they’ll still manage to put on good show, particularly if they get plenty of natural light and aren’t over-watered. (Dead-head regularly and hard prune in spring and they’ll be fit and ready to go and grow again outdoors).

So, as with all house plants, avoid the compost becoming too wet.

When the flowers start to form, apply a high-potassium fertiliser such as tomato feed. Temperature wise, most pelargoniums are quite happy as long as the thermometer doesn’t fall below 40F.

If you don’t want the flowers but still want the plants, lift them from the garden in autumn and cut them back to 10cm (4ins), making sure to remove all the dead and damaged growth.

Pot them up in fresh compost and keep over winter, in a light, frost-free spot. Water sparingly until growth resumes in spring.

Then re-pot them in new compost and harden them off ready to go outdoors when the threat of frost has vanished.

Many pelargoniums can be pinched back in spring or early summer to encourage them to grow bushy rather than tall and spindly.

Young plants of trailing ivy-leaved cultivars are best pruned back to promote branching.

Pelargoniums are easy to grow, but in pots they are vulnerable to attack from vine weevil and aphids; the former eat the roots and the latter suck the sap.

Poor air circulation and damp can lead to mould and fungus attack. So it pays to keep a weather eye on things and tackle problems before they become serious.