Before frost, it's time to plan plants' re-entry

Houseplants: After a summer outside, enjoying raindrops and compliments, tender greenery is ready to move back in.

September 30, 2001|By Nancy Taylor Robson | Nancy Taylor Robson,Special to the Sun

It's one of those end-of-summer rituals -- like buying school clothes or stowing the barbecue. Bringing in the plants. With the exception of the giant aloe that lives in the kitchen year-round, all my houseplants spend the summer outdoors. It's good for them and me. In summers like this one, they drink rainwater, and I enjoy the grace notes they add by the garden benches and perennial borders.

Some of these plants -- like the hemstitch begonia and the rose geraniums -- have made the spring / fall transition for years. Others, like the annual basils, I renew each year by potting up the least woody-stemmed specimens from the garden.

Like much of gardening, moving plants indoors is done in stages -- starting with those least tolerant of cold. The key, of course, is to know each plant's tolerance.

"This year people used a lot of tropicals in the landscape, which are very cold sensitive," says Donna Shipp, manager at Homestead Gardens in Davidsonville. "Plants like Chilean jasmine [Mandevilla], hibiscus, Chinese evergreens [Aglaonema], begonias and philodendron don't take cold at all. If it goes below 40 degrees, they start to have 'issues.' "

"Issues" can range from leaf burn and damaged stems to total collapse, though some can be nursed back to health by clipping off dead bits, watering, and providing light and steady warmth. Others, like the basils, are virtually unsalvageable.

"Basil doesn't like anything much cooler than 60 degrees," says Hildreth Morton, owner of Bittersweet Hill Nursery in Davidsonville.

The second wave of plants that need to come inside are more cold-tolerant things like lemon grass and geranium.

"Geraniums will even tolerate a frost, but it's better to bring them in before they get hit," Shipp says.

Hanging baskets can come inside, but Morton warns that by the end of summer, a lot of those cascading petunias and freesias are too root-bound to do well, let alone thrive the following summer.

"It's better just to start over next year," she says.

The last wave includes ivies -- which can stay out a long time, since they enjoy cool weather if they are protected from a hard freeze -- and rosemary which comes in both tender and hardy strains.

"Rosemary 'Arp' and 'Hill Hardy' can stay outside for all winter," says Morton.

"Just remember that winter-hardy rosemary is very sensitive to wind and drying out," says Jeff Brawn, garden center manager at Simonds Nurseries in Reisterstown. "You can protect the outdoor varieties with burlap."

Even winter-hardy plants can also suffer in pots in an exposed area.

"I would not leave anything in a pot on the deck and expect it to be living next spring because of it freezing dry," Morton says.

In pots, the roots of even frost-hardy plants are more vulnerable to solid freezing than in the ground. And, while many of these plants go into dormancy, they still need adequate water, a fact that many gardeners, happily ensconced in chairs by the fire, forget.

The shift from outside to inside is a good time to assess plants.

"Repot them if they are root bound," says Morton. "And for things like begonias, which have very fine hair roots, use a soilless mix -- peat moss, perlite, and vermiculite combined -- rather than garden soil. It allows more air to the roots."

Garden soil can also carry harmful spores and a potential insect hatch that will delightedly devour your newly repotted greenery. Shipp warns that plants that had bugs last winter are prime candidates for a renewed infestation. "Scale and spider mites tend to disappear in summer because there is air circulation and a lot of predators outside to take care of them," she says.

"It's a good idea to give plants a really good shower with a garden hose a couple of days before bringing them in," adds Brawn. "Then once you bring them in, watch them for a couple of weeks. If you see an infestation, take them back outside to spray them with insecticidal soap. That's safe for almost anything except the fuzzy-leafed things like African violet."

Finding the right place inside for plants will help ensure their healthy survival. Chinese evergreens have very low light requirements and can be tucked into north windows. Begonias prefer morning sun only, which means an eastern exposure.

"If they have too much sun, they blister," says Morton.

Things like basil and rosemary need south-facing windows, while some tropicals need more light than even a southern exposure offers during short winter days. For these, full-spectrum fluorescent light bulbs can help. Once the light requirement has been met, it's time to look at maintenance. Many plants benefit from a trim once they have adjusted to the indoors. For example, cut hibiscus back at end of October or beginning of November and then again in March so they stay bushy, but don't become woody.

"Hibiscus bloom on new growth," Shipp explains.

Then water regularly (moistening but not soaking is a general rule of thumb, though some plants like to dry out), and fertilize once a month.


Bittersweet Hill Nurseries

1274 Governor Bridge Road off Route 424

Davidsonville, MD 20135


Kingsdene Nurseries Inc.

16435 York Road

Monkton, MD 21111


Simonds Nursery Inc.

1141 Berrymans Lane

Reisterstown, MD 21136


Homestead Gardens Inc.

743 W. Central Ave.

Davidsonville, MD 21035

410-956-4777 or 410-798-5000

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