Prepare your favorite flowers for frost

GardeningSeptember 5, 2012 

Tradition has it that the first garden column of September covers what to do when the first frost hits. I can't swear to it but I suspect both Lenore Hedla and Mann Leiser, earlier Alaskan garden columnists, gave this advice in their columns as well.

When a frost is expected and before it hits, bring in fuchsia, tuberous and fibrous begonias, pelargoniums, impatiens and any "annuals" in your garden that you want to grow into and perhaps through the winter. Most annuals, it turns out, are actually perennials we treat as annuals. Most can be potted up and grown indoors provided you have a set of lights, which, of course, every reader of this column does.

Clean things up before you get inside. Look for slugs, in particular. They hide in and under plants and all over containers.

Fuchsia can be grown over the winter under lights or with natural light, though they won't flower with the supplemental light. Or they can be trimed to mirror the shape and size of their container and stored in a dark spot with temperatures between 40 and 50 degrees.

Pelargoniums can be kept going under lights and will also grow under natural light. Pinch them back to shape them. Or, try the bag trick: Place barerooted plants upside down in a paper bag or a box and keep with the fuchsia. In the spring, cut back dead "wood" until you hit green, cheer and re-pot.

Tuberous begonias can be stored in their pots with the fuchsias. It is best to let them die back gradually, so bring them into a garage or similar spot and let the foliage die back on its own. Then store with the fuchsia. Some folks dig theirs up at this point and store tubers in sawdust.

The loyal reader may note that this is a change in advice from previous years where I said it was fine to let begonias have a few frosts. It is true that tuberous begonias can take a few frosts. However, they are supposed to die back slowly so they can place as much of their sugars into the tubers as possible. Often a frost doesn't allow this to happen.

Similarly with dahlia tubers. Dig them up and let them die back in the garage, slowly. You can divide clumps in the spring. Just make sure that when you do clean them for storage in sawdust or individual bags, that you leave a few inches of stem.

Gladiolas can take frost. This is good because many don't bloom until the very end of the season. Dig them up and shake off, but don't wash the soil. Once they are taken in, allow the fans to dry, cut them back and store in sawdust or individual bags. In the spring, you will find a new corm under the old corm.

Fibrous begonias should be taken in and grown under lights. If you are lucky enough to have a rhodochitin, try growing it as well, if you have the room. Or you can store yours as you would a fuchsia. Collect seed pots and skip the trimming.

Hydrangeas are becoming popular. They can be wintered over as houseplants, under lights. If you keep them outside in the ground, build a cage over plants and fill with straw or other insulating material. Flowers come from the tips and these should not be damaged. Some folks suggest laying stems down and covering them up, praying for snow insulation and that no one steps on them during the whole winter.

Yacons in containers will continue to grow indoors all winter long and make terrific houseplants with huge, light green leaves. As noted, so can most annuals from petunias, cosmos, nemesis, impatiens, even snapdragons. What have you to lose by trying anything you have by way of annuals? Especially if you have lights, and, of course, room.

And, of course, don't forget about labels. You may remember what the plant is called this year, but I assure you, nine months of winter gets to a gardener's memory. Label everything.

If I left anything off you can contact me at www.teamingwithmicrobes.com/home or call in Saturdays from 10 a.m. to noon to Garden Party on KBYR radio, 700-AM, also podcast at kbyr.com.

Finally, I wonder about this "first column of September, frost alert column" tradition given the clear impact of climate change on Alaskan gardeners. Not only are we warmer in the traditional sense -- as in we even have 70 degree days like they do in, say, Seattle -- but our season has doubled in growing days over the past 100 years or so going from 60 to well over 120 days. That is why I am starting to add, each year, the following note to the column: Cut this column out or book mark it. Hopefully you won't need it for another month or so.

Jeff Lowenfels is the co-author of "Teaming With Microbes: The Organic Gardener's Guide to the Soil Food Web. You can reach him at teamingwithmicrobes.com/home or during his radio show, 10 a.m. to noon on Saturday on KBYR AM 700, kbyr.com.

Garden calendar

POTATOES: YOU CAN DIG THEM IF YOU MUST. WAITING JUST MAKES THEM SWEETER AND TASTIER. BEETS: WHAT ARE YOU WAITING FOR?

BROCCOLI GOING TO SEED: THOSE SEED PODS ARE TERRIFIC IN STIR FRY DISHES OR JUST STEAMED AND DIPPED INTO BUTTER.

LAWNS: THERE IS A SLIGHT DANDELION FLUSH. KEEP MOWING THOSE PATTERNS. OH, AND TAKE A FEW PICTURES OF YOUR LAWNS. GREEN, LUSH. KEEP THEM AROUND FOR NEXT SPRING WHEN YOU HAVE THAT KNEE JERK REACTION TO FERTILIZING AND LIMING.

ALASKA BOTANICAL GARDEN GARDEN HARVEST AND SCARECROW CONTEST: SATURDAY, 10 A.M. TO 4 P.M. DETAILS AT WWW.ALASKABG.ORG. NURSERY AND GIFT SHOP OPEN. (THIS EVENT MAY BE CANCELED DUE TO DAMAGE CAUSED BY THIS WEEK'S WINDSTORM. CALL 770-3692 EXT. 0 TO CONFIRM THAT IT'S HAPPENING.)

SOIL TEST: DO IT NOW. GATHER SAMPLES AND HAVE YOUR SOIL TESTED. TRY SOIL TESTING LABORATORY AGRICULTURAL EXP. STATION, UNIVERSITY OF ALASKA IN PALMER. PHONE: (907) 746-9482, PNLAW@UAA.ALASKA.EDU

SPRING FLOWERING BULBS: PLANT AS MANY AS YOU CAN AFFORD, BUT DO IT NOW.

PLANT A ROW: BRING EXTRA FOOD TO BEANS CAFE. FLOWERS TOO.

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