If you want to save some of your tender bulbs by storing them for spring, there is a relatively new method that is easy and successful. In the past, if you wanted to save bulbs and roots, it usually meant layering them in large containers with peat moss. This was especially true for dahlias and it was the American Dahlia Society that first accepted this new method, something they don't do on a whim. You will need sulfur, vermiculite and plastic wrap. Some of the bulbous rooted plants I have successfully stored with this technique are dahlias, cannas, alocasia, colocasia, tuberose, and acidanthera,so you see it works for a great many plants.
I prefer to dig up the roots before we have frost, we have already had a light frost (unexpectedly early), so it's definately time to get going. You have to remember that many of these tender bulbs are tropical and cold soil temperatures can set them back. Today I dug my tuberoses, cannas, alocasias and colocasias. Wash off the roots and let them dry in the sun.
The colocasia roots will often have a rhizome with baby tuber on the end, you can keep it intact or separate them. The tuberoses (right) have become very expensive, the few I dug today would be worth about $100. come spring, so YES, I'm going to save them.
Cannas need some wrestling to get them all out of the ground. I love Canna 'Bengal Tiger' and it's not always easy to find, so I dig them up every year.
Mix 1 part powdered sulfur to 8 parts vermiculite in a plastic bag.
I suggest you take off your jewelry, the sulfur turns all things silver - black. Cut the leaves off, as low as you can go. The remaining roots are tossed in the bag and coated by shaking. The roots will come out looking very yellow.
It's important that you give the roots a night to dry, preferably in a warm place. I sometimes coat them again the next day, if I see places that were missed. Lastly you wrap them in plastic wrap individually, don't let 2 bulbs or rhizomes touch. Masking tape works great to label what's in each bundle. I prefer to store the tropical roots in a warm place. I have found that the wall beside my freezer works well. Dahlias can be stored on the cool side, like 40 degrees.
As you store your sulfur/vermiculite mix for next year, you will find that the mix usually needs more sulfur, it seems to stick to the roots more readily. I keep the bag in the garden shed, ready for the next fall, when my tuberoses will be huge!
Why not use the sulfur alone?
Posted by: Donna Williamson | 10/17/2012 at 07:48 AM
The dahlia society's website says that too much sulfur can burn the growth tips or eyes, so the vermiculite acts as a filler. I also think that the vermiculite draws excess moisture to itself, away from the bulb. My old mix of 3 years was too damp to use, even though it had been stored in a dry shed. We all know that vermiculite absorbs moisture, so I'm guessing it's the best working additive.
Posted by: Karen Rexrode | 10/17/2012 at 02:22 PM
Great info - thanks!
Posted by: Donna Williamson | 10/18/2012 at 09:33 AM