Many of the summer flowering bulbs and tubers are considered ‘tender’ bulbs meaning that they are not hardy enough to stay outdoors through the cold winter months. Dahlias, Tuberous Begonia, Calla and Canna lilies, and Gladiolus all need to be taken indoors and stored in an area where the temperatures are above freezing if you want to be able to enjoy them again next spring/summer.

 

The time to bring in most of the tuber/bulbs indoors is after the first fall killing frost. Some areas of Prince George (including ours) have already had the first killing frost earlier this week. A frost will often blacken the foliage.

 

To save Dahlias for the next season, first cut back their stems to 15 cm (6 inches) above the ground after a frost has blackened the foliage. Then, loosen the soil around the tuber and lift it out of the soil, carefully, so that you don’t damage the tuber.

 

The tuber will have multiplied and these can be divided next spring.

 

Gently remove any excess soil from around the tuber and then place it upside down in a dry, airy, frost free space for 15-20 days. This will get the moisture to drain out of the stems and help avoid the neck from rotting. When it is dry, sprinkle the tuber with ‘Bulb Dust’ (an insecticide/pesticide) to kill any overwintering pests and disease and store it in a cool, dry, frost-free space.

 

Every few weeks check the tuber for rot, and if there is a problem with rot, remove the tuber from any other tubers and cut the rotten part out immediately. Treat the affected part with sulphur before placing the tuber back into storage.

 

When the frost has blackened the foliage on Tuberous begonias, carefully dig up the tuber and set it on paper and place it in a cool, dry area for a couple of weeks, and then cut back the stems to 10-15 cm from the tuber. Remove any excess soil from the tuber but don’t disturb or damage the tuber, a little bit of soil on it is fine. Keep the tuber in a cool, dry area, until the rest of the stems and foliage dry up and fall off. The tuber is now ready to be stored. Sprinkle some Bulb dust on it and place it in a container filled with dry sand or vermiculite and store it in a cool (6-10 Celsius) dark, dry space until February when it can be replanted again.

 

Calla lilies are grown from rhizomes. In order for these to be kept over the winter the rhizome needs to harden up before it is dug up. To harden it up, cut back on the watering after the Calla has finished blooming which will set the plant into dormancy. When the foliage has yellowed, the rhizomes are ready to be dug up. After carefully digging them up, remove as much of the soil from the rhizome as possible and then store them at room temperature for 7-10 days to further harden the outer shell. Sprinkle Bulb Dust on the rhizomes and wrap them individually in paper and then place them in a paper bag and store them in a cool dark area.

 

After a killing frost, cut back the foliage on Canna lilies to 15-20 cm from the soil. Dig up the rhizome and allow it to air dry before sprinkling Bulb Dust on it and placing it in moist sand, peat moss or vermiculite. Store the rhizomes in a cool dark location. Check them periodically to make sure that the medium it is stored in is still moist as you don’t want the rhizome to dry out.

 

Gladiolus flowers should be removed after they have finished blooming so the plants energy is not going into forming seeds. When the foliage has been affected by a frost the corms are carefully dug up and the foliage is trimmed back to 2 cm and the excess soil is shaken off the corm. Allow the corm to sit in the sun for a few hours to air dry and then place it in a cool area for a few weeks. When they are dry, the old corm is rubbed off the new corm and tossed out. The new corms are then sprinkled with Bulb Dust and then stored in a warm dry space.

 

Don’t forget to label all your tubers, corms, etc before placing them in storage so that next spring you will know what they are. To get a head start on summer next year, plant your summer flowering bulbs indoors in peat pots, in April and then plant them outside in May. 

 

 

Jos VanHage owns and operates two Art Knapp Home and Garden Centres in Prince George:

·        Highway 16 west at Kimball Road

·        Highway 97 North at Northwood Pulpmill Road