Committing Tree-icide: Water & Mulch

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(Don’t miss last month’s post about proper tree planting!)

Once we have the new tree in the ground, we want to do our best to help it not only survive but thrive. Knowing how dry our climate is, it’s natural to focus on providing enough water for the tree to become established.

A newly planted tree needs to be watered where its roots are. Those roots will be close to the trunk, which is why the landscapers set up their drip emitters to irrigate that area.

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Garden Advice: Don’t Prune that Crown!

Quercus_Oak_COS-CO_LAH_1854It’s a common question. You’ve just planted a new tree. In the process, the plant has lost a significant portion of its roots—sometimes up to 95 per cent! Should you prune back the crown to compensate?

The intuitive answer would be yes. We assume that with fewer roots, there’s no way the plant will be able to sustain all that foliage on top—and that’s the advice I see on website after website. But if you do decide to prune, you’ll be doing the tree a disservice. You might even kill it! How can this be?

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Watering Trees

dead tree_COS_PLH_3The tree had clearly expired. What leaves remained had turned a sickly yellow-brown, and hung limply on the branches—in mid-August! Yet, when our neighbors planted it last year it had been perfectly healthy. Something was obviously wrong, and I had a hunch I knew what. (I’ve often said that master gardeners kill just as many plants, we just know why they died.)

Surreptitiously moving the cobblestone mulch aside (and wondering if the homeowner was watching through the closed curtains), I looked at the drip irrigation set-up. There was only one emitter, and it was directing water right to the base of the trunk. No wonder the tree was dead! (That and the fact that it was planted too deeply; there’s no sign of the root flare.)

close-up tree irrigation wrong_COS_PLH_1

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Getting Established

Catmint established_COS-CO_LAH_1542You’ve read the instructions; I’ve used them frequently here in my posts. “Drought resistant once established.” Sounds good—we’re always trying to save water—but how should you water these plants to start with? And what does “established” mean?

There are a lot of misconceptions about xeric plants. Our landscaper (who was much better at dealing with hardscapes than with living plants) thought that our xeric shrubs and trees needed to be sopping wet for the first few years, until they were “established.” Dead, more likely. (I’m already having to replace some fernbushes that were growing in muck, and we lost the top half of our oak tree in the first few months.)

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Planting a Tree

Improper staking_LAH_5226How do you plant a new tree? Most people know to dig a hole “twice as wide and deep as the root ball” (according to the label I found hanging from the branches), then stick in the tree, making sure the roots are well buried. Amend the backfill with plenty of compost, pile it over the roots and tamp it down firmly. Finally, securely stake the thin trunk so it won’t wiggle in the wind. Right?

Wrong!

This advice was being questioned as far back as 1980, but it is still widely practiced, much to the detriment of the poor plants.

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Getting to the Root of the Matter

Phalenopsis orchid roots_DBG_LAH_6672We all know what roots are—they’re the part of the plant that’s usually underground. If we have a mental image, it’s probably a mass of wiggly, white strings poking their way through the soil. We should pay more attention to roots. After all, they’re an essential part of a plant (as well as the only part remaining after some hail storms!). Knowing a little about how roots work will make us more successful gardeners.

Before I get any further, I should point out that I’ll be talking about your average, every day root. Life is an amazing phenomena, so diverse that there are always exceptions. So let’s skip the orchids (left) and other epiphytes, and the mangroves and other plants with roots growing in water, and focus on our garden flowers, shrubs, and trees.

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Beyond Crabapples: Another Flowering Tree for Spring

Crataegus laevigata_English Hawthorni_HudsonGardens-CO_LAH_5810-001When it comes planting a spring flowering tree, most Colorado gardeners immediately think of crabapples. Wildly popular all along the Front Range, crabs deserve their stellar reputation. However, they aren’t the only flowering tree that thrive in our harsh environment. There might even be a better choice! Consider their close relative, the Hawthorn.

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March Flowers

Populus tremuloides - Aspen @DBG LAH 184As I write this, the temperature outside is 10 degrees. Wind swirls snow into the air and howls around the eaves. It’s hard to believe anything is in bloom. Yet, some Colorado plants choose March as their best time to reproduce. Specifically, many trees are currently in full bloom—and I bet you haven’t noticed.

Unlike the showy flowers we grow in our gardens, the flowers of cottonwoods, junipers, and elms are not designed to attract pollinators. Rather, they rely on wind to disperse their pollen. It’s a hit-or-miss proposition, which is why these flowers produce clouds of the stuff—enough pollen so that some lands on another flower’s pistil, and plenty left over to aggravate our eyes and noses. It’s the flowers you don’t see that are out to get you.

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