How to plant Dahlia

Thanks to varieties ranging from giant dinner-plate dahlias to compact gallery dahlias just 30-35cm tall, your garden can be a colour extravaganza during summer – whether you have extensive borders or pots to fill. They’re wonderfully low maintenance for the amount they give back – aside from the possible need to stake them if they have very large flowers, they’ll provide you with continuous blooms during summer and autumn with very little of fuss. And when you succumb to temptation and pick a few for the vase, the plants will eagerly replace the cut stems with new flowering shoots.

Dahlia planting basics

Dahlias love rich, well-drained soil in full sun. They’ll still give you lovely blooms without a lot of soil preparation, but enriching the soil by digging in a mulch when planting will give you even better results. Like most bulbs and tubers, they don’t like poorly drained soil, so dig in plenty of compost or topsoil to raise the level of your garden beds slightly if you have heavy soil.

How to plant Dahlia tubers

— Dahlias are half hardy, which means that should be kept frost free over winter and during spring.

— For best results, start your dahlia tubers in temporary pots in a greenhouse in March or April to grow on to transplant outside later in the season – this will give them a head start.

— Alternatively, you can plant the tubers directly outside in May.

— Plant with the stump of last year’s stem facing upwards. The tuber should be fully submerged but with the stump just below the soil surface.

— Plant one tuber per 8-10” pot if growing on during spring. When planting outside, space the tubers around 30-50cm apart from each other. Compact varieties don’t need so much space.

— Water-in thoroughly after planting and continue to water regularly once in full growth, but only when the soil appears to be nearly dry.

Planting instructions