Bulbs to Plant in Summer

How to Plant Summer Bulbs: The Golden Rules

Knowing how to plant summer bulbs correctly makes all the difference. Get the depth, soil, and drainage right, and your bulbs will have everything they need to thrive into a riot of colour throughout the season.

Planting depth: The rule of thumb is to plant at a depth of two to three times the height of the bulb. Here’s a quick guide:

•  Dahlias: Plant tubers 10–15cm deep

• Gladioli: Plant corms 10–15cm deep

•  Lilies: Plant bulbs 15–20cm deep (three times the bulb height)

•  Begonias: Plant tubers 5–7cm deep, hollow-side up

Soil and drainage:  Summer bulbs need well-drained soil to prevent rotting in your beds or containers. On heavy clay soil, dig in compost before planting, and add horticultural grit directly beneath and around bulbs, especially if you are planting dahlias and gladioli.

Tender vs. Hardy Bulbs: This is worth knowing the difference, as it affects winter care, so here is a simple breakdown:

• Hardy bulbs (e.g. some lilies) can stay in the ground over winter in mild areas.

• Tender bulbs (e.g. dahlias, gladioli, begonias) must be lifted after the first frosts and stored frost-free indoors until spring.

Can I Plant Spring and Summer Bulbs Together?

Can I plant spring and summer bulbs together? It’s one of the most common questions we hear. The short answer is not at the same time, but you can absolutely use the same bed. Spring bulbs are planted in autumn; summer bulbs go in during spring, making them perfect partners for a beautiful extended display.

A brilliant technique is lasagne bulb planting, which is layering spring bulbs (like tulips) deep at the bottom of your pot, adding compost, then planting summer bulbs like begonias or dahlias on top. Each layer emerges in turn for months of non-stop colour from a single container or bed. In borders, simply fill the gaps left by fading spring bulbs as the weather warms; by the time your tulips have finished, your dahlias will be ready to take over.