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FAQs for Winter Gardening: Home

Apiaceae; photo courtesy of Flickr cc/Grace Smith
Apiaceae; photo courtesy of Flickr cc/Grace Smith

Q.

What are some trees and shrubs with branches suitable for forcing indoors in the winter?

Cut the branches of forsythia, spirea, spicebush, quince, pussywillow and other early blooming trees and shrubs for forcing indoors. If you can keep them in a cool place and change the water at least once a week they will last longer and you will be rewarded with beautiful blooms for a few weeks. Try spacing your cuttings at two-week intervals so you will achieve a continual succession of flowering, thereby extending the indoor display well into late winter.

Spicebush (Lindera) is a suitable, early-blooming shrub to force indoors; photo by Ivo Vermeulen
Spicebush (Lindera) is a suitable, early-blooming shrub to force indoors; photo by Ivo Vermeulen
 

Q.

What are your suggestions for keeping houseplants healthy during the winter?

Place indoor plants in an area where they receive the maximum amount of light, but in some cases direct sun may be harmful. Some protection, such as a thin curtain or special sunshades, may be necessary, although winter sun is weak and rarely posses a significant danger of sunburn. Turn your houseplants regularly to keep them from becoming lopsided and gently pinch them to keep them shapely.

Group plants together to increase the humidity level during the dry winter months. Potted plants can be placed on a shallow tray filled with pebbles that are kept moist to increase humidity. Although it is very helpful to increase the humidity, do not let the pots sit in water. Keep the water level below the top of the pebbles. Most plants want to dry out and then be watered thoroughly. Be sure to have adequate drainage such as perlite or sand in the potting soil mix.

Like selecting a plant for your outdoor space, there is no substitute for choosing the right indoor plant for a specific growing spot in your home.

Q.

Do I need to apply a winter mulch to my landscape plants?

To reduce the effect of alternate frost heaving and thawing, apply a winter mulch after the soil freezes. When mulch is applied to frozen soil it will keep the soil consistently cold. Mulch will also help to retain soil moisture. The mulch layer should be 2 to 2 1/2 inches thick and can be composed of leaf compost, straw or other material.

Broadleaf evergreens, like Ilex opaca, continue to lose moisture through their leaves during the winter; photo by Ivo Vermeulen
Broadleaf evergreens, like Ilex opaca, continue to lose moisture through their leaves during the winter; photo by Ivo Vermeulen
 

Q.

What are the reasons for using an anti-desiccant on evergreen plants in the winter?

Evergreen plants, both narrow and broad leaf, continue to lose moisture through their leaves in winter. If the soil is frozen, ground moisture is not available to plant roots and they cannot absorb what is lost through the leaves. The foliage becomes dry and brown and may drop. Applying anti-desiccant coats the leaves and reduces transpiration. Usually two applications per season are necessary for protection, one in December and the other in February. Wrapping evergreens with burlap or canvas is also helpful to reduce desiccation from sun and wind. Leave the top of the wrapping open to allow sunlight to penetrate.

With their usual food source covered in snow, mice and rabbits may damage your trees and shrubs; photo courtesy of Flickr cc/Ronnie Meijer
With their usual food source covered in snow, mice and rabbits may damage your trees and shrubs; photo courtesy of Flickr cc/Ronnie Meijer
 

Q.

Why do mice and rabbits cause damage to landscape plants in winter and how can this be prevented?

During a period of extended snow cover, when their usual food sources are blanketed and therefore unavailable, these creatures seek out alternatives such as the bark of trees and shrubs. When partial girdling (cutting through the bark in a belt-like pattern) occurs due to this nibbling, insects and pathogens can gain easy access and weaken plants. If trunks and stems become completely girdled, the plants will die because water and nutrients no longer have a pathway from root to leaves. In order to prevent this kind of injury, wrap the trunks and stems of susceptible plants with plastic covers or hardware cloths. Alternatively, rodent repellents can be sprayed onto the trunks and stems. Be sure to reapply in midwinter, during a time of warm temperatures.

Pinus ponderosa; photo by Michelle Longo
Pinus ponderosa at NYBG; photo by Michelle Longo
 

Q.

I would like to make my own holiday wreaths and sprays this year. What plants are best suited for this purpose and how do I condition them to last?

To ensure their freshness, beauty and safety through the season, take appropriate steps in selection, conditioning and care of evergreen boughs. Wash branches thoroughly in warm water to remove dust and dirt, then rinse them in cold water. Remove any defective foliage and split the stems about 2" to 3" up from the ends to facilitate water uptake. Place the material in warm water and store in cool temperatures for at least eight hours prior to use. Keep the water level high by replacing any water that has evaporated from the container. All evergreen material will last longer if conditioned in this manner prior to use. 

Pines and firs stand up best indoors while certain species like hemlock and spruce are notorious for dropping their needles. For the best needle retention, choose Abies balsamea (balsam fir), A. fraseri (Fraser fir), A. procera (noble fir), A. concolor (white fir), Pseudotsuga menziesii (Douglas fir, not a true fir), Pinus sylvestris (Scotch pine) or P. strobus (white pine). 

Remember to cut off the invasive vine Celastrus orbiculatus (oriental bittersweet) that grows up and girdles trees. Take as much as you want; bittersweet's orange and red fruit adds an attractive touch to wreaths and sprays

Dahlias should be carefully stored over the winter (Dahlia 'Sweet Dreams')
Dahlias should be carefully stored over the winter (Dahlia 'Sweet Dreams')
 

Q.

What is the best way to store tender bulbs such as dahlia over the winter?

After the first hard frost, cut back the blackened stems and gently lift the clump of roots with a spading fork. To prepare them for winter storage, label each clump with the variety name and stand the clumps upside down to drain away any moisture. After about a week of drying, place them in a deep box and cover the clumps with slightly damp peat moss or wrap them in newspaper before storing. They are best stored in a place where the temperature is between 35 to 50 degrees. Be sure to examine the tubers for any rotting during the winter and remove decaying portions immediately.

Q.

What should I do with all of the garden sprays, powders and fertilizers that I have accumulated?  Can I keep them to use next season?

It is best to discard old garden products, especially those that contain chemicals. Keep current by checking with your local cooperative extension service on the new and approved kinds of pesticides and herbicides for your particular area.

Clean leaves of smooth, large-leaved plants with a damp cloth; photo courtesy of Flickr cc/Mark
Clean leaves of smooth, large-leaved plants with a damp cloth; photo courtesy of Flickr cc/Mark
 

Q.

I have noticed a lot of dust on my houseplants. What is the best way to clean them?

Clean leaves of smooth, large-leaved plants such as philodendron, ficus and dracaena with a soft, damp cloth to gently wash off any accumulation of dust and grime during the winter months. For smaller leaved plants, occasional misting with water will cleanse the leaves. You can also use a clean feather duster for this purpose, although this spreads the dust around. Using a Swiffer dust brush can help. Also, some people like to give their plants a shower in the bathtub. 

Cut away Celastrus orbiculatus (Oriental bittersweet) that girdles trees; photo courtesy of Flickr cc/Liz West

Cut away Celastrus orbiculatus (Oriental bittersweet) that girdles trees; photo courtesy of Flickr cc/Liz West

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