Oooh, that awful dry air in winter!

Houseplants and humidity

By Amy McDowell

When I was in charge of watering inside the dome at the Des Moines Botanical Center, I watered more than just the plants. I also soaked the concrete walls and pebbled paths. The plants, screaming for moisture, needed more than just a drink of water—they needed high humidity like the tropical rainforests of their origins.

During these cold winter months, the dry outside air is sucked into our furnaces, heated, and pumped through the heat vents throughout our homes. And just as we suffer with dehydration such as thirst, dry, itchy skin, tired, burning eyes and tender sinuses, our houseplants are suffering with dehydration that shows itself as curling leaves, dry brown leaf tips, yellow leaf margins, shriveling, wilting, bud drop and limp, weak growth.

The water that houseplants take up through their roots is used for growth, but much of the moisture is released, or transpired, through tiny holes in the stems and leaves called stomata. Winter air pumped through our furnaces is so dry that it rapidly taxes houseplants beyond their capacity. There are a number of things you can do to raise the humidity level and aid plants, and it doesn’t even require watering your walls and floors.

·        Humidifiers are the simplest and most effective method to raise humidity.

·        Group plants close together so they can benefit from each other’s transpired moisture.

·        Make pebble trays. Fill sturdy plant saucers with pebbles and water and place them around your houseplants. The pebbles create more surface area than just a dish of water so it will evaporate quickly.

·        Turn down the furnace. Plants will transpire less moisture if the furnace isn’t running as often. Also, keep plants away from heat vents and drafts.

·        If the kitchen or bathroom is bright enough, move plants there, where humidity is often higher than the rest of the house.

·        Misting plants is the least effective option. It is a short-term, temporary solution that must be repeated frequently throughout the day to even make a difference. In addition, water droplets on the leaves may lead to disease.

Aaahhh, those bloomin' indoor vines!

Blooming indoor vines

By Amy McDowell

The Linnaean House at the Missouri Botanic Garden is the most enthralling building I have ever set foot in. It is a brick-sided greenhouse built in 1916, proudly touted as the oldest continuously operating greenhouse this side of the Mississippi River. A brick path snakes through the center of the earth floor and plants on both sides of the path sink their roots directly into the ground. Vines clamor up the brick walls inside and outside the building. When the large wood-frame windows are left open in the summer, the scents of camellias and jasmine wisp in and out.

The earthen floor anchors plants and gives my soul an indoor soil connection far beyond potting soil in containers. Planting beds in the dome at the Des Moines Botanical Center are similar, but the scale of the Linnaean House creates an intimate, homey atmosphere. If only I could live in such a building.

I am left to recreate the divine environment on a pot-bound scale, but a handful of blooming vines cooperate with the conditions in my home. The following tender vines are some of the simplest. They require very bright light, like that in a southern- or eastern-facing window, and are content with average home temperatures and humidity. Most will bloom all winter with regular water, little fertilizer and an occasional trim. Spray to keep the bugs at bay. Once a month, use insecticidal soap or mix your own with a drop of dish soap and a teaspoon of rubbing alcohol in a 16-ounce spray bottle filled with water.

Black-Eyed Susan Vine (Thunbergia alata) originally bloomed golden with a dark eye. I grew it in that loud clashy color, but now they are available in tamer citrus colors, pink blush and pure white. The new colors look great beside the cool colors of Browalia (B. speciosa major) and trailing Lobelia (L. erinus). Browalia blooms with 1-inch blue stars all winter, and the Lobelia has dainty dark purple flowers.

Other vines that bloom indoors include smelly Lantana (L. montevidensis), ivy geranium (Pelargonium peltatum), red-and-white glory bower (Clerodendrum thomsoniae), finicky Fuschia (F. magellanica gracilis), delightfully fragrant snail vine (Phaseolus caracalla) and fan flower (Scaevola aemula).

Amaryllis

Showy and Vibrant Amaryllis

By Amy McDowell

My first amaryllis only bloomed once and then it died. Yes, I followed the directions. I tucked the bulb, pot and all, into a cool dark closet and left it there—too long. Oops. By the time I pulled it out of the closet, the bulb had shriveled up to a dry papery husk. It turned out the directions were poor and I had guessed wrong on a few of the important details. It was years before I grew amaryllis again, but I’m so happy I gave them another try. Here’s how to do it right so they will bloom year after year for you.

Potting Amaryllis

·         Amaryllis blooms are stunning, but buying three bulbs and planting them all in a wide, shallow pot is even more breathtaking.

·         Buy quality potting soil. It will work much better than that light, dusty peat mix that comes in amaryllis kits.

·         Place the bulb so that the top half is above the soil level. The bulb needs to have about an inch of space on all sides.

·         Water it well over the sink, and then set it in a warm location. If you set it on top of a warm appliance, like the refrigerator, the bottom heat will push it to flower more quickly. Don’t leave the pot on a bottom heat source for more than a week.

Care after Blooming

·         You can remove the blooms as they fade, but wait until the bloom stalk starts to whither and collapse before cutting it off.

·         The bulb will still have leaves, so treat it like a regular houseplant until spring.

·         In late May or early June, set the pot outdoors in a shady spot where you will remember to water it. You will have healthy green leaves all season, which are making energy for the next bloom cycle.

·         In late September, let the pot go a little drier, and then in early October, take it into a cool dark basement. You are pushing the bulb to go dormant and rest for about eight weeks. Don’t cut the leaves off until they have turned brown on their own. Little or no water is needed.

·         In early December, bring the pot out. You only need to repot the bulb if it is bursting out the sides of the pot. Water thoroughly, and the blooms are on their way again.

Amaryllis are available with single blooms, double blooms, and in miniature. They come in red, orange, pink, peach, blush, white, and bicolors. You can find amaryllis at the local garden center, or by contacting any of the following sources: Amaryllis Bulb Co. at 888/966-9866 or www.amaryllis.com; McClure & Zimmerman at 800/883-6998 or www.mzbulb.com; John Scheepers, Inc. at 860/567-0838 or www.JohnScheepers.com.

Amy McDowell is an Iowa Certified Nursery Professional. She has an associate’s degree in commercial horticulture and has worked in the field for ten years. She lives and gardens in Polk County.

 

Tropicals and Frost

Tropicals, take cover. F – f – frost is here.

By Amy McDowell

It’s time to blast the bugs off and bring your tender houseplants inside. Use a one-two punch on those insects to make sure you don’t bring them into your home. First, sprinkle systemic insecticide granules on the soil. When you water, the systemic is absorbed by the plant’s roots and circulated throughout the plant, making it toxic to insects. A systemic can last in the plant’s system for three months. Your second punch is to wash the plants thoroughly—tops and bottoms of the leaves and all along the stems—with a firm blast of water from the hose. Soft-bodied insects like aphids and spider mites can’t survive an aggressive washing. Let the plants drip dry outside before taking them in.

No doubt your tropical plants have grown over the season. You may want to prune and reshape them before taking them inside. Many plants suffer shock from being transferred indoors – you will see the telltale leaf drop. Pruning before you relocate them will not only improve their appearance, but may reduce your leaf cleanup later.

Dig ‘em up

Tender bulbs and tubers should be dug up and stored now – things like cannas, dahlias, and gladiolas. After our wonderful regular rains throughout most of the season, you will find those canna tubers underground are now huge. Pry them out of the ground with brute strength and as much gentleness as you can; they will bruise. Cut the stems back to about four-inch stubs, brush the soil off, and store them in an uncovered crate or open box in your basement. The care is the same for dahlias and glads.

Put ‘em in

Spring bulb sales in the U.S. have been declining for several years, and people in the industry believe it may be because spring bulbs don’t provide the instant gratification that other flowers in the garden do.

Here in Iowa, we tuck bulbs into the ground in October and wait for about six months before we see their bright blooms in spring. Who needs instant gratification? Just knowing those spring bulbs are nestled in the ground under the ice and snow gives us something to look forward to all through the blustery winter.

Even just a few dollars spent on a handful of bulbs can provide a cheery bouquet next spring and for many springs to come.

Amy McDowell is an Iowa Certified Nursery Professional. She has an associate’s degree in commercial horticulture and has worked in the field for ten years. She lives and gardens in Polk County.