A guide to the best begonias | Daily News

A guide to the best begonias

Begonias are a fantastic summer plant to grow, and very rewarding. In the British climate they will flower abundantly from June right through to October. As such versatile plants they look fabulous in pots or containers on the patio, or equally as beautiful in a flower bed.


Most varieties grow best in a mild temperature range, between 15°C and 26°C, though tuberous begonias need it a little cooler to perform at their best. They like humidity and warmth, but can’t tolerate extreme heat, dryness or frost.


As a general rule, begonias favour bright filtered light with no exposure to harsh midday sun. Some species will also tolerate deep shade. They need good ventilation to help prevent fungal diseases and do well planted under trees and shrubs. Some of the cane-stemmed and wax varieties will tolerate full sun.


In the garden, they require free- draining soil improved with compost. Heavy clay soil that becomes waterlogged is unsuited, as it can cause root and stem rot. In pots, use a light free- draining potting mix containing coco coir, perlite or vermiculite (African violet mix works well).


Begonias have fleshy stems and leaves that hold water for long periods of time, so they don’t need constant watering. Too much water can cause plants to turn brown and rot, so allow them to dry out almost completely between waterings. Try to water the soil around the plant and not the foliage, as wet leaves can encourage powdery mildew.


For potted plants, apply a general-purpose slow-release fertiliser at the time of potting and liquid fertiliser at half-strength every two to three weeks during the growing period. In the garden, it’s advisable to incorporate a general-purpose fertiliser into the soil at planting time.

Three essential care tips for begonias

Begonias are fairly robust but you will need to look out for and treat these problems to keep your plants in tip-top shape.

* When buying begonias

Inspect the plant carefully for any signs of disease or insect damage. If it looks weak and leggy, or has any holes, spots or discolouration on the leaves or stems don’t buy it, as it will not thrive.

* Powdery mildew

This fungal disease shows on the tops and undersides of leaves as a grey/white coating, and they eventually wither and die. Water the soil around the plant and avoid splashing the leaves, watering in the morning so any excess moisture can evaporate during the day. Remove any affected leaves with sterilised sharp scissors or secateurs. There are commercially available sprays that are useful in treating this disease.

* Burn marks

Dark brown, crisp looking marks on leaf edges are usually caused by low humidity. Place the pot in a tray with pebbles and water, making sure the pot base doesn’t sit in the water to prevent root rot. Begonias also get sunburnt, seen as a pale brown or yellow scorch mark on all, or part, of the leaf. Cut off the leaf and discard and move pots into a more sheltered spot, or give garden plants a new position that doesn’t get direct midday sun.

Insects Slugs, snails and green lopper caterpillars like to have a meal on their leaves. Treat the slugs and snails with bait and pick off the caterpillars. White fly, mites and scale can also be a problem, treat with an appropriate chemical spray, checking the label to for application rates.

Better Homes and Gardens