Tender Summer Bulbs Need Tough Love

Planting summer bulbs indoors gives weeks more colour from your flowers in the summer garden.

Credit: courtesy Netherlands Flower Bulbs

Summer bulbs such as canna, calla lilies, begonias, dahlias and gloriosa are among the most dramatic flowers in the summer garden.

They’re easy to grow, but are also very sensitive to frost. So sensitive, in fact, that they’re called tender bulbs. The good news is that tender bulbs respond incredibly well to a little tough love! Wake them up early and get a jumpstart on summer by potting them up indoors. It’s easy to do. This simple head-start will afford you weeks more colour from your bulb flowers in the summer garden. Summer bulbs are available as bare bulbs for planting from late winter through late spring and as pre-grown bedding plants in pots in late spring through summer. Tender summer bulbs can be started indoors four to six weeks prior to the usual last local frost date and then planted outdoors to begin their regular summer growing season.

Tips to Get Growing!

1. Select bulbs (true bulbs, rhizomes, tubers, roots) that are firm to the touch. 2. To get earlier blooms, pot them up indoors to start growing about six weeks before your planting-out date, the date in your area when the threat of night frosts is past. Choose clean containers with drainage holes – good drainage is essential. Use a commercial potting soil mixed with equal parts peat moss and sand or perlite. 3. Place bulbs in the soil mix, following the planting directions suited to that type of plant. Different types of summer bulbs require very different planting methods. For specific details related to planting depth and positioning, look for instructions on the bulb packaging or go to our Summer Bulb Primer. 4. Warm humid settings are optimal for growth. Keep soil moist, but not wet. 5. Once the threat of frost is past, transplant tender bulb plants to the garden or outdoor containers. Summer bulbs prefer warm soil, close to 15° C (60° F). This soil temperature is generally reached once nighttime temperatures have stayed at/or above 15° C (60° F) for about two weeks.

Don’t miss our Summer Bulb Primer

Including 18 of our favourite bulb picks

While dates for the last frost vary throughout our province – last year saw Vancouver and Victoria’s final frosts at the end of March, the Fraser Valley’s in mid April, and Kelowna’s in mid May, while Prince George, Kamloops and Dawson Creek endured nippy nights until early June – everyone benefits from starting their bulbs inside before transplanting them out. Naturally, the dates vary year to year, so be cautious: your soil should be well warmed and the last frost long gone before you set tender bulbs into the ground.

Summer Bulbs to Start Indoors

Achimenes (magic plant) Aesaema arisaema (cobra lily, jack in the pulpit) Agapanthus bareroot Agapanthus small pots Alocasia Alstroemeria (Peruvian lily) Amaryllis belladonna Begonia Bletilla (Chinese ground orchid) Caladium Canna Colocasia esculenta (elephant ear) Crinum (swamp lily) Crocosmia (montbrecia) Curcuma (gingers) Cyclamen Cyrtanthus (vallota) Dahlia Eucharis (Amazon lily) Eucomis (pineapple lily) Gloriosa lily Haemanthus Hymenocallis (ismene) Incarvillea (hardy gloxinia) Liatris Oxalis Polianthes tuberosa (tuberose) Ranunculus Rhodohypoxis Sprekelia (Aztec lily) Zantedeschia (calla) Zephyranthes (rain lily) Xanthosoma (elephant ear)