Storing tender bulbs

Details

Published on Sunday, October 26, 2014

By Patricia Hanbidge

    Saskatoon School of Horticulture Principal

Now that autumn is moving towards winter, there are still a few chores that should be completed. If you enjoyed the glory of tender summer-flowering bulbs, it is now time to give those bulbs some special treatment in order for us to preserve them so we can enjoy their beauty again next year.

Tender bulbs are those plants that have fleshy storage structures (bulbs, corms, tubers and roots) which will meet their demise over winter if they are not brought indoors out of the extremely cold winter temperatures. It is important to dig up these structures and bring them into a warmer area for storage throughout the winter.

For most of the plants we may grow, it is best that they be lifted after the foliage is killed by frost or has dried up. Dig the bulb structures carefully to ensure they are not damaged. Loosen the soil on all sides of the plant before lifting the clump of roots and soil without damage. Cuts or other damage will allow disease organisms to enter which is not advisable for good storage.

Most bulbs are best dried with the soil still adhered but if you are storing dahlia or canna bulbs, it is advisable to gently wash the soil away from the root tissue. Gladiolas are an exception in that they should not be washed but allowed to dry thoroughly before gently removing any soil that is adhering.

Most bulbs will need a curing period before storage. Dahlias, cannas, callas and caladium need a short period of drying (one to three days) in a room that is away from direct sunlight and winds that are drying. Gladiolas and oxalis will need about three weeks of drying at just under room temperature in a dry but well ventilated area. Ensure you examine all tissues; those that are infested or soft should likely be discarded.

It is important to label all stored plant material to ensure there is no confusion in spring. I personally like using paper bags for storage as labels are easily written on the outside. Throughout the storage period, check regularly for any rotting or other damage.

Acidanthera spp. is a corm and should be stored at around 35 to 40F (1.6 to 4.4C)

Begonia x tuberhybrida is a tuberous root and should be stored at approximately 50F (10C). Store in sphagnum peat moss or vermiculite.

Caladium bicolor is a tuber and should also be stored at approximately 50F (10C). Cure with remaining foliage and store in peat or vermiculite.

Zantedeschia spp. or calla lily is as rhizome and is also stored at approximately 50F (10C). If possible, let foliage dry off a few days before digging. Store in sphagnum, peat or vermiculite.

Canna x generalis is another rhizome that should be stored between 40 and 50F (4.4 to 10C). Dig after frost has damaged foliage and let the plant dry a few days after digging.

Dahlia hybrids have tuberous roots and should be stored between 40 and 50F (4.4 to 10C). Cure in high humidity and pack roots in sphagnum to avoid desiccation.

Gladiolus hybrids are corms and should be stored between 35 and 40F (1.6 to 4.4C). Cure two to three weeks prior to storage.

Hanbidge is a horticulturist with the Saskatoon School of Horticulture and can be reached at 306-931-GROW(4769) or This email address is being protected from spambots. You need JavaScript enabled to view it. .

Like us on Facebook and get in on all our upcoming events; follow us on Twitter @horticulturepat or visit saskhort.com.