Best Horticultural Tips for February
Trees and Shrubs
- Zonal geraniums have a “zone” on the leaf that can be faint or dark, narrow or wide. The most important thing you can do to keep geraniums colorful is deadhead them. This includes the ones you are overwintering inside.
- Looking for a gardening project during these cold days? Try propagating the geraniums you are wintering over. Select a sturdy stem. Cut at a slant just below a leaf node. Carefully pinch the leaves off of the two lowest nodes. Place in damp potting soil in a clean plastic pot. Firm the stem in the center of the pot with both exposed leaf nodes below the soil line. Cut half of each remaining leaf off at a diagonal so that the plant invests the majority of its energy into creating roots. Take a large zip lock bag and set the pot in the middle. Zip the bag half to three-fourths closed. Blow into the bag while holding it up to your mouth so that it fills out like a balloon. As quickly as possibly, zip the bag closed when you remove it from your mouth. (You may need to practice this a few times.) Once the bag is zipped, set it under grow lights or in a bright window. What you have created is a mini-greenhouse. The moisture from the potting soil will form droplets on the top of the bag and then water the cutting. It may take one month to fully root. Note: DO NOT OPEN THE BAG TO CHECK ON IT. Once the plant begins to set new growth on top, you will know it has developed roots. This propagation method works with many, many plants. Good luck with your experiment!
- Some houseplants develop “aerial roots” which will cling to many surfaces. If you want to try to propagate those plants, follow the directions above, but instead of using soil, place the stem in water to allow the roots to fully develop. No need to cut the leaf surfaces in half or place it in a bag. The water in the jar will provide the necessary humidity.
- Give houseplant a one quarter turn each week when you water to ensure all sides receive adequate light. If plants are getting “leggy” pinch them back.
- Tulips, daffodils, and hyacinths are readily available at many stores in our area. Buy them to enjoy the blooms now. When blooms fade, deadhead the plant and move the pot to a cooler area, like the garage. Water lightly once a month. When spring comes, plant the bulbs at the proper depth in your garden. They will greet you the following spring.
- If succulent plants are losing leaves, it could be due to overwatering. Allow the potting soil to dry out between waters. Or try watering every other week.
- Boston ferns like a consistent moist potting soil and high humidity level.
- Why might other houseplants lose leaves over winter? Lowlight level, cold drafts, low humidity, excess heat source, abrupt changes (like moving the plant to a different window), and standing water in the saucer.
- When overwintering geraniums as potted plants, cut back in mid-March by ½ to 2/3. Place in a sunny window or under fluorescent lights.
- Repot houseplants that are root bound in a 1-inch larger pot. Jumping up several pot sizes may actually harm some plants whose roots like to be “cozy.”
- Treat yourself or a friend to a new houseplant as a mid-winter pick-me-up. Look forward to the Orchid Club Sale at Lauritzen Gardens in early March.
- This time of year keep an eye out for whitefly, mealybugs, and scale on indoor plants. Be ready to respond with neem oil, insecticidal soap, or rubbing alcohol and Q-tips. Several treatments will be necessary to take care of adults and the new hatchlings that emerge from the potting medium.
- Water indoor plants with room temperature water.
Trees and Shrubs
- Conifers like dawn redwood, larch, and bald cypress are deciduous and will drop their needles in winter.
- Be knowledgeable before pruning conifers because they DO NOT replace growth like other trees and shrubs. Remember, trees are an investment. When in doubt, call an arborist.
- When planted in the right place, weigela rarely need pruning. Just thin out some of the stems to reduce the size of the bush.
- Forest trees rarely have large lower limbs because of the lower light intensity. When trees are forced to grow alone, people have to take over that function. Hence the necessity of arborists to limb up and thin out the one tree in front of the house.
- Light is a critical resource for a tree, but not all tree species require the same light intensities to function. This is why some trees are sold as “understory” trees. They need a taller species around them to provide shade.
- While winter keeps you out of the garden, this is a great time to check out The Hidden Life of Trees by Peter Wohlleben (2016). This is an intriguing look at the communal aspect of nature. Wait until you find out how trees actually communicate with one another!
- Prune only small branches of new trees; start early. Once limbs become larger it is better to call an arborist.
- Avoid the temptation to prune trees and shrubs on a warm winter day.
- If you over prune a new tree it can starve to death since pruning causes loss of stored food and loss of storage space. Trees are a lifetime investment. It is best to check with an arborist.
- Turf roots have six times more density than tree roots, so keep sod 3 feet from trunk of tree.
- While it is fine to prune many trees in the winter months, avoid pruning spring flowering trees or shrubs until after they bloom.
- Trees absorb moisture and steal nutrients from the soil underneath their canopies. This is why it is so difficult to grow grass under large trees. If you are constantly replacing or reseeding the grass in such an area, use the winter time to investigate what kind of groundcover or low growing plants you can replace the grass with. It is smarter to work with nature than to fight it.
- Leaving the stems on some perennials, like penstemon, helps them to survive the winter. Standing ornamental grasses and plants also catch the snow, which offers some protection to birds. This has been particularly noticeable this winter.
- Things to consider: This is the best time to order caladiums. While originally for the shade, many varieties have been bred for full sun. Order now for the greatest variety of colors. Many sources are available online, but a very reliable one is http://fancyleafcaladiums.com.
- Check out those catalogs. Now is also a good time to research catalogs for native plants and grasses that you can add to your garden this year. Why go native? Native plants have been proven to increase not only the numbers of bees and butterflies but also the number of different birds that will visit your yard. Good online sources include http://prairienursery.com and http://prairiemoonnursery.com.
- Start seed throughout the winter depending on growth requirements.
- Check stored bulbs for rot and decay and discard damaged ones.
- Remember when the weather gets “bad”: perennials are protected under a good blanket of snow during the cold temperatures.
- There are always a few nice warm days during winter, but do not rush the garden chores. The soil is not warm enough to plant perennials until the Japanese maple leaves begin to unfurl—and that is a long way off. Meanwhile, walking on partially thawed garden ground will just compact it.
- Offer the birds clean water in a heated birdbath or heated dog dish. Investigate the requirements for having your yard certified as wildlife habitat by the National Wildlife Federation.
- Assess the winter beauty of your yard from inside your warm house. Where could you plant dwarf evergreens, native or ornamental grasses, or shrubs like red twig dogwood and yellow twig dogwood to stand out against the snow?
- Chlorosis is a reduction in green color or yellowing of a plant due to a nutrient deficiency or disease that inhibits the formation of chloropyll, the green pigment in plants. This can happen inside or out in the garden.