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About Planting Summer-
and Autumn-Blooming Bulbs
Timing and Tips for Planting
Plant summer- and autumn-blooming bulbs in spring to develop their roots, grow, and burst into flower during their respective calendar seasons.
Warm weather marks the start of planting time for summer- and autumn-blooming bulbs. Warming of soil lags several weeks behind the arrival of warm daytime air temperatures, longer if cool evenings persist late into the season.
Wait until the soil warms thoroughly to plant most summer and autumn bulbs. To be certain, wait to plant the other summer and autumn bulbs until the air temperature remains consistently above 60°F (16°C) for at least 10 days.
Lilies are an exception, because they are hardy. Lily bulbs also tend to dry out when stored. Buy them early in the season, and plant them immediately.
If you must store lily bulbs and tubers for a time, lodge them into slightly moist peat moss. Store them until they can be planted in a dark area with a temperature of about 40°F (4°C) [see Curing and Storing Bulbs].
The remaining tender bulbs—tuberous begonia, caladium, calla lily, canna, dahlia, and gladiolus (shown)—sometimes sprout early growth before planting conditions are right.
If this happens, go ahead and plant them, protecting them with a floating row cover or mulch whenever frost is likely, or, in milder climates, apply insulating mulch.
Keep the row-cover material off the ground by driving stakes across your planting area at regular intervals. This allows air warmed by the soil’s heat to circulate under the cover.
Remember to thoroughly water new summer and autumn bulb plantings. Irrigation after planting restores moisture the bulbs have lost, compacts the soil around the bulbs, and triggers the end of dormancy.
Apply mulch to the planting area to provide a neat appearance, retain moisture, insulate the soil, and block weed germination [see Mulching Landscape Bulb Plantings].
Taller summer-bulb species—dahlia, gladiolus, and lily—will require stake supports to protect them from wind. Install the stakes after shoots emerge. Add ties as they grow. The ties should allow some stem movement, to help promote sturdy stems while helping the plants resist breakage.
Tuberous Roots and Rhizomes
Several species of summer and autumn bulbous plants are not true bulbs, but bulblike plants with special roots. They are called tuberous roots and rhizomes [see: Bulbs Basics].
Most tuberous-rooted and rhizomatous species sprout foliage from growth points or crowns atop their roots. Because they are not as drought-tolerant as true bulbs, they are usually available in nursery containers.
Careful division of the crowns and replanting multiplies the number of plants—and flowers—for your garden. You’ll get more plants for your landscape, year after year [see: Dividing Bulbs and Roots].
These tuberous-rooted plants and rhizomes required entirely different planting methods compared to other bulbs. To plant them, note the special planting instructions for these species [see: 7 Ways to Plant Bulbs].