Storing Delicate Tender Bulbs for the Winter
One of the tasks I drag my feet starting is to dig my tender perennial bulbs. I no longer grow more than just a couple of these. I think it is more than the labor. I don’t have a lot of outside chores except cutting down dead trees, raking leaves, building ponds, laying out new planting beds for next year, you know just the normal everyday puttering tasks. I could easily fit in digging more of these plants. I rebel against any plant that requires extra attention. Yet, there is a great deal of beauty in these plants. I would miss them if I did not spend a bit more time and effort protecting them. After all, it isn’t their fault they are growing in an unnatural habitat.
This year I have a dahlia and I have canna that sprouted from some outside over wintered seed. I want to save this canna to see if it or any of its progeny are more winter hardy. This is the hybridizer/seed saver in me. I just can’t resist encouraging outlier phenotypic expressions in plants (in other words I am looking for a detail about the appearance of a plant or flower I want to encourage in future generations). That is how we now have more winter hardy Alstroemeria. Zone 8 was about the best one could hope for this plant only 25 years ago. Today some sources claim a Zone 6 tolerance for some cultivars. And, don’t forget the daylily folks. They are at the top of the “finding rare chance attributes” and encouraging these to become dominant traits. Remember that yellow and orange are the species color for daylilies. These daylily hybridizers have given us almost every color, form, size, textures anyone will love to grow.
When to Dig
Another reason I procrastinate digging is for two reasons. Because these are non-native plants and most still look great. They still want to grow. They are probably just now blooming well. It took them all season growing to be able to bloom. They still look like summer when everything else is dying back, turning yellow, getting ragged.
The second better reason you can procrastinate a bit is because it doesn’t hurt the plant to let the frost knock down the top. You will be saving the root, tuber or bulb. These are protected with the surrounding soil. Soil cools more slowly than the air. You will want to dig shortly after a killing frost to be safe. I do want to admit waiting one particularly warm autumn until Thanksgiving before digging bulbs. That was a miserable situation I don’t want to repeat. The canna roots were just fine. Be sure you don’t let the ground freeze. That will kill the bulbs for sure.
Cutting Back and Washing
Digging is the first thing you want to do. Carefully start at least 6 inches away from where the plant is coming up out of the ground. I prefer to use a garden fork. In my mind there is a chance that if I am too close then the gap between the tines will keep damage to a minimum. The garden fork is easier to use than a spade.
Whether you are digging before the frost kills the top or before it is important to remove the top growth. Try to cut close to the bulb. Leave just a little bit. I don’t want to risk defoliating so closely that I accidentally damage the top of the bulb. This could harm next season’s plant.
Use your own sense of quantity. I have grown some of these plants for quite a number of years. I don’t ever have visitors in the fall anymore. Everyone knows I will be pressing bulbs on them. They are polite enough to just stay away. Little do they know that I learned from this and only dig enough for myself next spring. Well, I guess I save about double what I know I want to plant . . . just to silence the neurotic voice asking “What if . . .?” questions in my head. You will see quite a number of very small bulb-lets when you dig your gladiolas. Most won’t make it through the winter without rotting. If they do, because they are so small, they can’t be buried very deep or they won’t have the energy to send up a shoot. Toughen your heart and toss these in the compost.
I’m a firm believer in washing the dirt off of these tender bulbs. I do this for several reasons. The first is that I don’t want any “bugs” and worms. Second, I sometimes nick these when digging. It is hard to tell if I have accidentally damaged any of these bulbs. A good washing will help identify boo-boos. They should be removed. A sliced canna root will rot and sometimes take all the rest of the conjoined roots with it. It is best to break off damaged parts.
Drying and Storing
The last big reason for washing your bulbs is that before you store them, they should dry a bit. I use this drying time to keep an eye out for bruising or other damage. I want to catch this trouble before it has a chance to impact any of the rest. These don’t need to dry out too long. After a week or so they should have dried sufficiently to store them. This is a curing phase that helps keep them alive but dormant for the winter. Perhaps you will have remembered this when you dug, cleaned and dried your daffodil bulbs last spring. If not, we will go over this procedure after about Memorial Day. That’s when I dig spring bulbs.
Storing is the part I have had to learn over the years. When I first began storing my roots and bulbs I tried to just leave them all dumped together in a box. There was considerable loss. The ones that were exposed to the air unprotected usually dried out. Some rotted. The rotted ones impacted any others they touched. Then for a couple of years I dug without washing them. Again those that were exposed to the air often dried out too much. What I noticed is that some that were surrounded by dried dirt had a better chance of making it through the winter in good shape. I noticed that the protective dirt must have kept them from too much air.
After much fine tuning I found that the best method for storage was to take the slightly dried bulbs and carefully layer them in a pot with some good potting mix. I like something that is pretty airy. I know you are saying: “Why wash them”? It really does help. The brief drying time is important too. Drying happens more quickly when all the dirt has been washed off. However, about once a month or so you will want to give them just a little bit of water. It doesn’t take very much. The little bit restores what the bulbs lost to the surrounding soil. Too much water of course will cause rot or early growth, both of which should be avoided.
I have had incredible success over wintering my tender bulbs using this system. I hope it helps you too.