Planting summer-flowering bulbs

Where to plant summer bulbs?

Plant them in rich, well-drained soil as stagnant moisture encourages bulb rot, in a sunny position and sheltered from winds. Don’t hesitate to plant them in groups of at least 5 to 7 bulbs for a more beautiful effect!

When to plant summer bulbs?

Plant frost-sensitive bulbs preferably in pots. In open ground, wait until the end of severe frosts between late April and mid-May, depending on the region, before planting. You can also speed up their cycle by planting them in pots under shelter and frost-free as early as February, to transplant them into the garden when the weather improves (around June in northern France). To learn more, feel free to check out our advice sheet: Preparing summer bulbs

How to plant summer-flowering bulbs?

Planting summer bulbs, whether in pots or in the ground, is quite straightforward.

How to plant them in pots?

For container growing, opt for dwarf and compact varieties where possible and consider installing a stake if needed at planting time to avoid damaging the bulb(s) later.

• Pot size varies depending on the type of bulb, but choose one at least 40 cm in diameter. Dahlias grow vigorously—allow for just one dahlia per pot (which you can pair with other summer-flowering bulbs depending on the dahlia’s vigour). Alternatively, plant three dahlias in a large container, such as a half-barrel.
• Ensure the pot has adequate drainage holes;
• Add a layer of clay pebbles or gravel;
• Place a piece of felt to separate the drainage layer from the compost, preventing it from clogging the holes;
• Prepare a light mix of good garden soil and compost, using a 25-75 ratio or 100% compost if you don’t have garden soil. Add some river sand if needed to improve drainage;
• Fill the pot with the substrate;
• Arrange the bulbs in a staggered pattern and plant them at a depth of 2 to 3 times their height;
• Water to keep the substrate from drying out completely, but avoid waterlogging;
• Apply a bulb-specific fertiliser, avoiding high nitrogen content, which promotes foliage at the expense of flowers.

How to plant them in the ground?

• Start by loosening the soil with a hoe, digging fork, or broadfork;
• Plant your bulbs at the appropriate depth based on their size, typically 2 to 3 times their diameter. Use a bulb planter or trowel;
• Place the bulb and cover with 5 to 10 cm of soil, depending on the variety, spacing them according to their mature size;
• Add organic fertiliser at planting time;
• Water regularly to keep the soil from drying out completely.

Aftercare

Remove faded flowers as they appear. Allow the foliage to yellow naturally to replenish the bulbs and ensure next year’s blooms. In autumn, bulbs planted in the ground should be lifted before the first frosts and stored in a cool, dry place, while potted bulbs should also be moved to shelter.

Pascal’s tips: In pots, you can plant summer bulbs in layers. For this, check out our tutorial on layered bulb planting. Finally, don’t hesitate to plant in groups for a stunning garden display!