Dear Helen: I think I need to dig up and store my dahlia tubers for听the winter. How is this done? Is the same true for gladiolus corms?
S.M.
Where soils drain efficiently of excess moisture and do not harbour high populations of soil pests, dahlia tubers usually store well over the winter when left in the ground, with mounds of insulating soil, shavings or sawdust over them.
Then came last winter, with its series of heavy frosts. Home gardeners lost many marginally hardy plants and roots, perhaps not to the first one or two waves of freezing temperatures, but finally to a later one. Some gardening friends lost all their in-ground dahlia tubers. I lost just some of mine. Now, gardeners are wondering what to do this fall.
We may well return to our usual, more moderate, weather this winter, but I suspect that cautious gardeners will be digging their dahlias for safe storage.
Wait for the first frosts to blacken and wilt the dahlia foliage. Then cut the stalks down to within 15 cm of the ground and carefully lift the tuber clumps. Let the clumps dry a little, with the stalks pointing roughly downward to help drain their interiors of collected moisture. Brush away clinging soil around and between the tubers, and re-cut the stem to just above where the roots join it, leaving the stem base intact.
Store the clumps in open plastic-lined boxes, covered with vermiculite or sawdust, in a dark, dry, cold but frost-free spot, ideally around 5 C. Check the roots periodically during the winter. Spray-mist lightly with water and move the tubers to a colder location if they begin to soften.
Divide the clumps in the spring when buds appear. Cut them into planting pieces, each one with a sprout and at least one tuber. The clumps can be divided in the fall, but the divisions are more prone to dehydration and mould in storage than are whole clumps.
Every time I鈥檝e written about digging and storing gladiolus corms for the winter, I get a deluge of mail from gardeners who never bother digging the corms. Their plants regrow nicely in the spring. Last winter may have changed that.
Lift gladiolus corms after the first light frosts. Cut the tops off right away, close to the new corm. Set the corms single-layered in a warm (around 26 C), airy place for two or three weeks. Then twist the old, spent corm away from the base of the new one and return the harvested corms to warmth for another week.
Store the corms exposed to air in open trays, bags or shallow boxes, in a dry, dark place at five to 10 C.
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Dear Helen: Can I dig and divide overgrown clumps of rhubarb now, or should I wait until spring?
P.G.
October and March are the preferred times for lifting rhubarb clumps and replanting young, outside portions of each clump in deeply dug sites that have been generously plumped with compost and/or aged manure.
As long as soil temperatures remain fairly warm and the weather is mild, there are advantages to taking on the project in October. The rhubarb divisions will have time to begin establishing new root systems before winter. Also, because early spring is a busy time in home gardens, it is nice to have the rhubarb project done.
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GARDEN EVENTS
Plant identification and culture. The Horticulture Centre of the Pacific (HCP), 505 Quayle Rd. in Saanich, is offering the next session in this ongoing, monthly course (can be joined at any time) on Saturday, 1 to 4 p.m. In each session Diane Pierce introduces 25 new plants, with descriptions, preferred growing conditions, landscape uses and maintenance. Cost to HCP members per session is $35, others $45. Cost for 12 sessions: members $350, others $450. To register call 250-479-6162. hcp.ca.
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Pro-D day camps. The HCP is offering garden programs for children ages five to 12 on teachers鈥� professional development days (Oct. 20, Nov. 24, Feb. 23, April 20) from 9 a.m. to 4 p.m. Featured will be seasonal gardening activities as well as nature and crafts projects. Cost is $38 per child. Register at 250-479-6162.
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Family harvest festival. Seasonal activities, games, and exhibits for the whole family will highlight the HCP鈥檚 annual harvest festival on Saturday, Oct. 28, 9:30 to 11:30 a.m. The endangered species chosen to explore this year is the Blue-Grey Taildropper Slug. Cost per family is $15. Space is limited. Register early at 250-479-6162.
