We store our summer bulbs because they are not winter hardy compared to our spring bulbs, which generally are planted in the late summer and fall months so they will bloom for us the following spring. these are also different from those late summer to fall bulbs that also are hardy.
Summer bulbs are planted after the danger of any late frosts have passed in the spring and are generally dug back up as the summer changes to fall, either just before or just after our first light freezes or even killing frosts each fall.
Gardeners generally call these plants summer "bulbs," but a few are tubers or a modified root and not an actual bulb. Caladiums, amaryllis, calla lilies, elephant ears and gladiolus are actual bulbs. We plant begonias each year, as most are annual; yet we also plant a tuberous begonia that will need to be dug up and overwintered. Another tuber would be the dahlia. On a side note: a couple of unique plants that require being overwintered are bananas and shamrocks – bananas dug up from outdoors and the pot of shamrocks allowed to go dormant and then stored.
Back to the summer bulb story now. Summer bulbs have been stored in unheated areas of the home. Two good examples would be a cold crawl space or an attached, unheated but insulated, garage, where they are placed on the top shelf near the ceiling where temperatures never fall below freezing. Conditions for storage this winter have been warmer than usual because of our mild winter temperatures. It also was warmer longer last fall outdoors.
If you have not visited those summer bulbs since you put them away last fall, you may be surprised to find them already growing! This is going to be a real problem because you likely do not have a place to continue to grow them indoors and it is certainly too early to plant them anywhere outdoors. Any foliage showing now is likely going to be white in color, tender and elongated. These bulbs respond to temperatures, so if you can get them into a cooler location, perhaps off the top shelf and onto the garage floor, then they should slow down.
Bulbs like amaryllis will be attempting to bloom. Go ahead and pot up the amaryllis bulbs. Bring them into the brightest part of the home and enjoy the bloom, as you cannot stop the growth of the flower stalk. Later, plant them outdoors along with your other summer bulbs coming out of storage.
About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.