Here are the plants you should get ready to pull out of the garden and bring inside

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: September 6, 2018
  • Published September 6, 2018

A begonia soaks up sunlight. Anchorage’s Horticulture Complex May 22, 2017. Fibrous begonias you may have in your garden beds also make great houseplants. (Marc Lester / Alaska Dispatch News)

This is the column I dislike writing every year, and I suspect the regular reader dislikes it more than I do. It is, of course, the annual "what to do when frost hits" column. Global warming may have delayed its advent, but winter and the end of the growing season are coming.

Which plants need to come in before a hard frost is predicted? That is the key question to answer. Our meteorologists are infallible when it comes letting us know when to act, so you probably won't miss the announcement. Besides, most gardeners can feel when a frost is imminent.

Houseplants are the first thing that you should bring in. Now might be time for that, so you don't risk them getting damaged by the colder nights we are now experiencing. Look for hitchhikers, especially slugs and aphids. And, if your plant needs transplanting, do it now while you can still do it outdoors. When you bring them inside, isolate these houseplants from other plants that stayed inside just in case you missed some critter or another.

Next, fuchsias and fibrous begonias and pelargoniums (geraniums) are tender and don't appreciate getting hit by freezing temperatures. Fuchsia should be taken to one of the nurseries that will store them, or you need to put keep them in the garage for a couple of weeks while the foliage dies back. Then they can be trimmed and put into a dark, cool (40 to 50 degrees) storage spot for the winter. You can keep them as houseplants, and they will bloom if you provide them with enough light.

The pelargoniums can be grown as houseplants, but they need to be cleaned up and perhaps pruned a bit. (You can root the cuttings in damp sand or soil if you let them them callous over for a few days first). They can also be repotted into indoor containers. Or, you can carefully remove them from their pots, shake off excess soil and place them upside down into paper bags. Store these in a dark, cool spot until next spring, when I will tell you to get them out and show you how to restart them.

The fibrous begonias you might have in your beds make great house plants, so don't just leave them out there, treating them like annuals. You can pot them up into individual containers or put a bunch of them into one. Give them light and they will bloom all winter long. No need to buy them for the holiday season.

Dahlias, tuberous begonias and gladioli easily make it through a couple of frosts. In fact, since the cold temperatures convert sugar supplies in the upper parts of the plant to starches stored in the corm or tuber where they are used next season to start up again, a freeze or two probably helps.

Bring the begonias indoors and stop watering them. The leaves will die and drop off and the stems will blacken and mush out. After a couple of weeks, put them in the proverbial cool and dark location. It is probably best to leave them in their containers, at least for the time being. In mid-winter, if you want, you can dig them out, but keep them in the dark, cool storage.

Each dahlia tuber you planted this spring will now be a whole bunch of them clinging to the plant's stem. Be careful when you dig up these plants, then bring them indoors and let the foliage die back. Cut it off once it does and then — you guessed it — store the entire clump in that dark, cool spot. Keep track of the varieties if you can, lest you decide to enter the state fair next year. Either put them into paper bags which you can label or use a marker and write on the tubers. Do not wash off the soil, by the way.

Gladioli can really take a hard frost and will continue to grow after even a few. If yours have not bloomed, leave them be. If they have, dig them up, toss the old bulb, but keep the new one that you will see has developed. Or just store the whole thing in paper bag with a label.

What have I Ieft out? Coleus has become popular. It will be killed by a frost if you don't bring it inside — where it will make a great houseplant. You can actually bring in any annual that is still in flower or has buds on it. We enjoy sweat peas clear up to Thanksgiving. If you have lights to put them under, annuals will most probably surprise you and continue to flower for a while.

The Alaska State Fair vine, rhodochitin, can be stored, as can fuchsia. Look for seed pods, however. Hydrangeas, of course, make terrific house plants. You might even want to dig up some of your herbs and pot them up to use this fall. Again, lights to grow them under will help.

Finally, if you are growing cannabis that is not day-neutral, you will have to decide what to do with your plants. They won't set buds until the daylight is less than 12 hours. Unless we have a very late frost, this means you most probably will have to move them indoors and put them under lights (for less than 12 hours a day). You might as well start planning for the move now.

Jeff's Alaska garden calendar

Garlic at the Alaska Botanical Garden: It is almost time to plant (mid-September). Stop by the Alaska Botanical Garden from 11 to 4 p.m. Monday, Sept. 17, to sample garlic and then buy bulbs to take home and plant.

Potatoes: Wait for a frost to get a sweeter harvest, though you can get at yours now if you want.

Carrots: What are you waiting for? Harvest.

Help the less fortunate: Now is the time to harvest those "Plant A Row For The Hungry" plots and distribute your excess. Real gardeners share and don' t let food go to waste. They surely don't feed moose!

Spring flowering bulbs: Buy as many as you can plant! There are plenty to be found locally, but remember there is a shortage this year.