Hedges to keep the neighbors out

Thorny rugosa roses can fortify garden boundaries

By Amy McDowell

It was an otherwise quiet evening at the garden center. The after-work crowd had slowed as people headed home for dinner. The summer sun far in the western sky cast long shadows across the parking lot. I was monkeying with the bird feeder display when the bell on the door jangled, and I turned to greet a well-dressed woman in a tailored brown business suit. She approached with a frown.

“Do you sell poison ivy plants?” she asked.

“Poison ivy?” Surely I had heard her wrong. She must’ve said Boston ivy.

“Yes, poison ivy,” she said. “Can I buy poison ivy plants?”

I lifted my eyebrows and mentally reminded myself how stupid I look standing with my mouth hanging open. “Um, no, we don’t sell poison ivy,” I said, studying her brown eyes closely for signs of insanity.

“Oh.” Her shoulders fell a little. “Then how about seeds? Do you sell poison ivy seeds?”

“Uh, no.” I said, and finally caved in to my bafflement and asked why she wanted to grow poison ivy.

“It’s my neighbors,” she said. “They’re always cutting through my back yard. It’s even fenced and they climb right over!” She waved her flawless painted nails in the air and her diamond ring glittered under the fluorescent lights. “I yell at them and they act like they don’t understand English,” she said, “but I know they’d understand the international language of ITCH.”

I breathed a sigh of relief. She was not a lunatic, just bonkers and sick of being trespassed. When I couldn’t help her, she left the store exasperated.

I’ve since come up with the perfect remedy… rugosa roses. These fast-growing beauties are covered with barbaric thorns. The stiff stems are ferocious from ground to tip. Rugosas form a rounded thicket four to six feet tall and wide. Planted three or four feet apart, they make an impenetrable hedge.

Better yet, the fragrant fuschia, pink or white blooms in the summer are followed by red or orange rose hips in the fall. In Latin, ‘rugosa’ means ‘wrinkled,’ a name fitting the crinkled dark green foliage. Fall color is usually short lived and yellow, but some rugosas turn orange or red. Rugosas are among the most disease free of all roses, so they don’t need any pesticide sprays. Annual deadwood pruning in spring is the only care they require.

Rugosas prefer well-drained soil in full sun or light shade. Hardy from zones 2-7, rugosas are wintertime tough. They’ve “been seen 100 miles from the Arctic Circle in Siberia where the temperature regularly falls to –50 degrees Fahrenheit,” writes woody plantsman Michael Dirr in his Manual of Woody Landscape Plants, 1990, Stipes Publishing Co.

Because of their vigor and easy care, rugosas are used in hybridization programs for new roses.

Next time someone asks me about poison ivy to keep interlopers from the yard, I’ll be ready with a suggestion. The wicked prickly thorns of beautiful rugosa roses will keep even the most brazen intruders at bay.

Repotting Houseplants

Houseplants on the Windowsill

By Amy McDowell

Houseplant is such an ordinary name for something really wonderful. They are one of the delights that sustain my itch to garden in winter. My favorites are the philodendrons, and I have a collection of ten different kinds. There are hundreds of species of philodendrons, from tiny vines with thumbnail-size leaves to climbing monsters that can cover a home in a tropical environment.

There are two main reasons I dearly love philodendrons. I love the way the new leaves emerge and uncurl. That tender new growth reaching out reminds me of spring. And best of all, philodendrons are rarely targeted by insects. I have never had insects on my philodendrons, although some of my other houseplants get to be a mess with pests.

This is the time of year I work on repotting. With only mountains of catalogs, books, and magazines to keep me occupied, I enjoy working my hands into the potting soil.

Most houseplants are happiest when their roots are somewhat snug in their pots, but it is a good idea to slip the root ball out of the pot annually to take a look. I generally repot a plant once every three to five years.

The standard rule of thumb is to only go one pot size larger when repotting. If you transplant into a much larger pot, the plant sits in the center of all that new soil and struggles to overcome the transplant shock. The excess soil surrounding the roots holds too much moisture, and that can lead to root rot.

Many gift plants come in decorative sleeves that don’t drain. You’ve got to toss the sleeves right into the wastebasket and give your plant a pot with good drainage and a saucer underneath so you can dump out the excess water. The pot doesn’t have to be fancy—a healthy houseplant will become the focal point and a plain plastic pot will fade into the background.

Tending to houseplants is one of winter’s joys. With a little care, your windowsill garden can carry your spirit through until spring.

One born every minute

Suckering trees and shrubs

By Amy McDowell

In horticulture, there’s one born every minute. And there I was in the front yard in the chilly knee-deep February snow, pruning the suckers from around the base of my spring snow crabapple. I had read that if you prune suckers during the winter months they don’t grow back as quickly.

As the weather warmed in spring, tiny red buds emerged at the base of the trunk, and soon enough skinny suckers were growing up at the base of the tree again. Exasperated, I realized I’d been had—the only thing that had delayed the new shoots was winter.

Suckers are not all bad. Most of my favorite shrubs have a suckering habit that results in a broad mound of growth and a beautiful shape when mature. There are a great number of suckering shrubs, including lilacs (Syringa species), Hydrangeas, Spireas, pussy willow (Salix discolor), serviceberry (Amelanchier arborea) and bottlebrush buckeye (Aesculus parviflora). Many of these form dense thickets that create wonderful privacy when used as hedges. Frequently, you can dig the suckers from around the base of the original plant and use them to extend plantings around the garden.

Staghorn sumacs (Rhus typhena) ablaze in red and orange right now, and elderberry (Sambucus canadensis) sucker to form large, open colonies. Both are fairly aggressive for a small garden, but regular lawn mowing at the edge of the colony is all that’s needed to fight back their spread.

Suckers are a sign of a plant’s genetic vigor. A non-suckering shrub like purple-leaf sand cherry (Prunus cistena) can fall prey to collar rot in heavy clay soil, but if it had the ability to sucker, young new stems would keep the shrub alive as the older stems succumbed. If sand cherries suckered, it would vastly improve their durability and longevity in central Iowa landscapes.

Despite all of the great suckering plants out there, it’s still tough to come up with an advantage to the raggedy suckers at the bases of crabapple trees. Tender rabbit fodder, I guess, to slow their attacks on the tasty trunk bark.

You don't always have to plant in drifts

Rebel against the rules of gardening

By Amy McDowell

“Welcome to Plant Collectors Anonymous” announced the crinkled paper sign on the door. One edge was smudged with what looked like a dirty thumb print. A ring of beige metal folding chairs sat in the middle of the room, cold on my tush as I took a seat. Before long, the circle filled and latecomers had to dash to another room and clumsily drag in a few more chairs. The gardeners were a motley crew—young and old, tailored and frumpy. They sat and smiled awkwardly at one another, hands in their laps carefully twisted to hide the dirt that was, without exception, under their fingernails.

And the confessions began. One after another, each gardener rose and gave his or her first name, followed by that aching mantra, “and I’m a plant collector.” Oh! The shame! Would we ever conquer our collecting ways and plant properly, that is, in drifts? It was embarrassing, for sure. In our rambling plant passion we bought what we loved and we loved whatever little beauty caught our fancy on our many, many garden center junkets. Our gardens, packed with a hodgepodge of plants, wantonly violated the rules of good garden design.

It wasn’t until I heard Tony Avent speak at the Western Nursery and Landscape Association that I shook off my shame and proudly, defiantly, lifted my chin. Tony owns Plant Delights Nursery in Raleigh, NC, and confessed that he grows thousands of different plants at his home. And no two are the same. None. No plants in masses or odd-numbered drifts. Onesies everywhere. And he showed slides to prove it. Slides of a gorgeous garden.

“I admit it, I’m a plant collector,” he said. And then he said if we think plant collecting is bad, our whole value system is screwed up. “What gets people more excited than plants?” he asked. They grow bigger and more beautiful and you can divide them and share them with your friends. You can’t do that if you collect antiques, he says. Then he even trumped the old “you shouldn’t buy a plant unless you know where it’s gonna go” nag with a sharp, succinct, “What kinda crap is that?”

Aaah. Now that’s my kinda guy. Let loose the “should” and “shouldn’t” gardening rules and have fun again. Like when I was a girl of seven in my favorite Bugs Bunny jeans planting marigolds. (Before I learned that growing marigolds is taboo or amateurish or just not done.) Back to when I planted my first Clematis and delighted in every leafy tendril, every bud and, as they opened, every bloom.

Whoever made up the rules needs to learn to love gardening again. And the rest of us need to learn to follow our passion and forget the restrictive rules for gardening. I’m thrilled that I have the audacity to say this with pride: “My name is Amy, and I’m a plant collector.”

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).

Trees and Construction

Building your dream home on that wooded lot

By Amy McDowell

Wooded residential lots cost thousands more than treeless lots, but if those trees aren’t protected during construction, they can be severely damaged. Often the damage isn’t visible and the slow physiology of trees means they may live for four to seven years after construction crews have left the site, slowly spiraling into decline and finally death.

Soil compaction from heavy equipment and building materials is the most common damage. Ninety percent of a tree’s roots are within the top twelve inches of soil. Soil compaction may crush or tear the fine roots, but the loss of air space within the soil profile can be long lasting and even more devastating. Soil organisms can take decades to loosen compacted soils and return them to a healthy environment for tree roots.

The most important step to protecting the trees on your building lot is to ring them with a barrier that is not easily moved by construction crews. Metal stakes and bright orange snow fence works well. Place the barrier at least one foot from the base of the trunk for every inch of trunk diameter. For example, a tree with a two-foot diameter trunk must have a barrier at least 24 feet from the trunk.

Even after construction is complete, continue to guard the root zone. Don’t let a finish grader add or remove soil within the barrier zone. If you seed or sod the new lawn, use care not to drown the tree by irrigating too frequently. After the turf is established, water no more than once or twice a week.

A three-inch-deep mulch ring around the tree will protect the trunk from mower and string trimmer damage, and the wider the ring the better it is for the tree’s roots. Some arborists say a mulch ring that runs clear to the drip line of the branches would be a tree’s dream-come-true, although they realize that much mulch is unrealistic for most homeowners.

For large construction sites with complicated traffic patterns around trees, you might want to consult with an ISA certified arborist on how best to protect the trees. Information is available at www.isa-arbor.com or 800-ISA-TREE.