Patrice Peltier is a contributing writer for State-by-State Gardening magazines.

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Why Do Plants Fail?
by Patrice Peltier    

Even experts can kill plants—which is why Roy Diblik offers seven common reasons perennials die.

It’s happened to us all. We have plants (usually the prized, expensive ones) that grow for a season—or maybe a few years—and then they die. Why?

A patch of neglected new plants. If you spend the money to buy the plants and take the time to put them in the ground, then it’s important not to forget them. Be diligent about watering.

Often, the reason boils down to this:  we’ve paid too little attention to what the plant really needs and perhaps too little attention to what we can realistically provide.

If you’re willing to invest enough money, time and effort, you can grow any plant—for a while—says plantsman, author, garden consultant and Know Maintenance™ guru Roy Diblik. Eventually, though, a plant in the wrong soil, light or moisture conditions will give up. “You have to be thoughtful about the conditions you are asking the plant to live in,” Diblik says. “Often, we’re asking plants to do more than they can do.”

A grower for more than 30 years, Diblik laughs when he says he’s an expert on killing plants. He’s had plenty of failures of his own and been called upon to help homeowners and landscape contractors alike solve their plant problems. Based on all that death and destruction, Diblik offers these insights into why plants fail.   

1. Wrong Soil 

Generally, we’re not as effective as we’d like to believe in changing soil conditions to suit the plants we want to grow. If you have clay, you may think you can add 3 to 4 inches of compost and instantly create loamy soil. Not so, according to Diblik. “You can’t change soil from bad to good in one year,” he says. It is possible to improve soil over time, as annual applications of organic matter are worked more deeply into the ground through the freeze/thaw cycle, the action of plants’ roots and our own digging.

What’s a gardener with poor clay soil to do? Instead of making plant selections based on the soil you hope to have, Diblik recommends starting with plants that grow well in the existing conditions. As your soil improves, add plants suited to the new conditions.

Diblik calls this a “layered” garden. “A layered garden develops year after year as you add plants suited to the conditions you currently have,” he says. He recommends that gardeners stop thinking in terms of creating a garden in a single year. “Your garden is never finished,” he says. “If you want something to be finished, take up bowling.”

Planting beds along concrete sidewalks are going to absorb extra heat and dry out quickly. Smothering with mulch makes things worse.

2. Wrong Moisture 

Be realistic about how much time you’re willing to spend watering, Diblik advises. If you think you can get away with planting moisture-loving perennials in a dry site because you’re going to water every day, you’re setting yourself up for failure—or at least frustration. Plus, even if you’re diligent about watering, your frequent irrigation may set up conditions that cause other plants to decline. Depending upon the plant, too much moisture can cause as many problems as too little. Know your conditions and know what plants need, he recommends.

“Make goals about your watering regime,” Diblik advises. “Once your garden is established, you may want  to water once a week or only in July and August when it’s dry. Then, select plants that will thrive in those conditions.”

A geranium drowning in wood chips.

3. Wrong Mulch 

“There’s not a plant on earth that evolved in wood chips,” Diblik is fond of saying. Yet many gardeners insist upon growing perennials surrounded by a thick layer of wood chips. Wood chips use nitrogen as they decompose, so they actually compete with plants for nutrients, he explains. What’s more, mounding wood chips around a plant can keep its crown from developing. 

“Plants evolved growing up through their own leaf litter,” Diblik asserts. That’s why he recommends mulching with ground-up leaves. If the leaves are local—or better yet, from your own yard—that’s even better. Using local resources is more environmentally friendly than trucking materials over great distances.

4. Too Much Fertilizer 

Plants grown in containers need frequent fertilization, but not so for plants grown in the ground, Diblik says. Just as with people, problems result when plants get a diet that exceeds their nutritional needs. Too much fertilizer can cause some plants to become floppy while others put on excess foliage to the detriment of flower production. At Northwind Perennial Farms, the Burlington, WI nursery Diblik co-owns, the palnts in the extensive display gardens are not fertilized at all. The nutrients they need come from added organic matter, he says.

5. Too Little TLC 

It takes most perennials two years to become truly established, according to Diblik. “You’ll hear people say, ‘I watered it for three weeks,’ and then they wonder why the plant fails. Of course, you’re not doing the same things every week. You have to understand how the plant develops. You change your watering, for example, as the plant develops. You don’t just water every day. You have to develop a relationship with nature. You have to pay attention to the rainfall, the heat, the plant’s growth and adjust your watering accordingly.” 

6. Too Much Romance 

Every gardener falls in love with something that’s blooming the day they visit the garden center or with the newest plant introduction they’ve seen in a magazine. Diblik calls those “romance plants.” The problem with romance plants is that they may not fit our existing soil types, or maybe they need more light or moisture than our site provides. They may not be reliably hardy in our area or grow well in our humid summers. But we’ve fallen in love, and we can’t be denied. 

It’s fine to succumb to the occasional romance plant, the plant you’re going to have to baby, indulge and cajole to keep happy. But a garden full of them?  That can lead to a gardener who’s overwhelmed with work and unsatisfied with the results.

Instead, Diblik encourages gardeners to select plants that thrive in a garden’s existing conditions with a minimum of maintenance. Then, if you fall in love with a plant here and there, add it knowing that it will require special attention, and, even then, may not be long-lived.

This dying plant was placed too high in the soil.

7. Too Much Work, Too Little Fun

Sometimes plants fail because the gardener has created too big a task. There’s too much to take care of. Impulsive plant selection may mean aggressive plants are taking over, self-sowing plants are coming up all over the place, high-maintenance plants are in decline, and short-lived plants have died, leaving gaping holes everywhere.

Often, as gardeners, we expect too much of ourselves and our gardens, Diblik notes. “Your expectations have to build with the garden. You are going to evolve with your garden. Have a simple beginning and let it build. Ask yourself ‘How much fun am I having?’ as you go. The whole point is to have a place to escape where you can be your own best friend,” he adds. “If this isn’t fun, what are you doing?”

“All plants want to live. They’re not dying because they’re suicidal,” Diblik says. Selecting plants that suit your current site conditions, mulching with leaf litter, watering as conditions warrant—especially during the plant’s first two years—and limiting yourself to what you can comfortably maintain will lead to plants that live happily ever after. And gardeners, too.

From Chicagoland Issue XVI Volume VI. Photography by Roy Diblik.


Posted: 12/12/12   RSS | Print


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