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).