Monday, 20 October 2014

How To Over-Winter Glads, Dahlias, Canna's and More....

Is just about time to lift all your tender summer blooming bulbs, corms and tubers for the winter... canna lilies, calla lilies, dahlias, begonias, eucomis (pineapple lily), and gladioli.

Here in Nanaimo, on Vancouver Island, garden zone 7, we can leave our dahlias, glads, and callas in the ground year round ...  but we do so knowing that a tough winter may cause us to lose some or all of them (some of the dinner plate dahlias can be quite tender).

Always lift your Canna lily bulbs, begonia tubers, and Pineapple lily bulbs. 

If you live in a cool garden zone, cooler than a zone 5, you will need to lift all those bulbs, corms, and tubers each fall in order to not lose them over winter.


I always lift my glads in fall as I grow them in the potager, amongst all the vegetables in the raised garden beds. They are moved around from year to year, planted wherever I feel the need for more height, colour, and/or pollinator attractors.

Glads just pulled and being hosed off from excess soil and grit.

How-to over-winter...

You want to wait about 6 weeks after the blooms finish to lift your glads. Ideally, the foliage will have started to yellow. If you can, have the time, and the patience, wait till the first frost hits them before lifting. 

If you have loose and friable soil, smoothly but gently pull them out of the ground by their foliage.

If you have heavy soil, or clay soil, is better to loosen the soil around the plants with a garden fork first and then gently lift them. Do not push the fork in too close so as to pierce the corms, damaged corms will rot and not cure properly.

Brush off the soil or wash down with the hose.

Cut back the tops to about 6 inches long.

Lay them out to cure in a warm, dry area with good airflow... if placed in a cold, humid area, they will not dry properly, this will lead to rot and mould.

I used to use my furnace room before I had the greenhouse. Lay them out on newsprint or cardboard, never on the bare concrete, and leave to cure for 2 to 3 weeks.

I now lay them out on wooden tables in the greenhouse, but a bright shed would do the same, or a warm garage. Always lay down some newsprint first, do not place directly on concrete or you may get rot. 

 Glad corm with wee cormlets
When fully cured (dry), remove the little cormlets, trim the roots, and trim the tops. If the old corm is still attached, remove and compost.

You can keep and plant the cormlets in spring, if you want. They will take 2 to 3 years till they size up enough to flower, so you may want to have a 'nursery' area in your garden where you can let them grow and be, lifting each fall and cleaning them up to plant again in spring.

Place the dry, cured corms in an ice cream pail, box, or paper bag with some barely moistened peat moss, potting mix, or pet cage shavings.



Basically, treat as you would the glads, see above.
After lifting the tubers, I hosed them down to remove all grit and soil.

I then trimmed off all the smaller tubers, the stringy long roots, and any damaged tubers. Remove the mother tuber as it will not flower again, larger tubers can be cut into two to make for more plants next year, as long as each piece has an eye or two (like potatoes). 

Placed them to cure on this wooden table, in the heated greenhouse, for 2 to 3 weeks.

When ready, they go into a box, with some lightly moistened potting soil, get pushed under one of the tables and forgotten about till late winter.

Check on them in late winter for any rot or shrivelling or new growth.
If you see rot or if they have died and dried up, toss them in the compost bin.
If you see sprouts, you need to deal with them right away. As soon as I see growth, I pot them up into 2 or 3 gallon pots, and leave in the greenhouse to grow on till the weather outside is lovely. When all risk of frost is over and the soil is warm, the dahlias go back into the garden beds.

If you lift in fall and pot up in spring, you will have blooms much earlier in the year than if you leave them in the ground.   


Treat as above for the glads...

May be left in the container if they are container grown...
Leave outside till frost has blackened the foliage and then cut back all growth to soil level. Bring the container in some place dry where the temp remains above freezing but not too warm. Ideally around 5 to 8 C.  


All summer blooming tubers, corms, and bulbs can be stored the same way. Clean, cure and pack away some place warm and dry.

Don't forget to label! You can either label by writing directly on the tuber itself with a Sharpie or label the box, bag,etc ... that you are storing them in.

Canna lilies bursting forth in spring

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