Everything You Wanted To Know About Gardening

Thursday, January 18, 2007

Choosing Healthy Plants and How To Get Them In!

How to buy new plants and not waste money

Before you pay money for a plant at a nursery or garden center, there are a few things you should get in the habit of doing. First, inspect the leaves. Blooms (on a flowering plant) are of little consequence at this point. If you are buying a plant in its growing season, it will continue to bloom if cared for. Brown, dried, or papery leaves indicate plant stress. If you see a large number of plants with damaged leaves in that store, grab your keys and leave. That's not a place you want to spend money.

Look under the leaves. Many pests in the garden are introduced by new plants! If you see zig-zag lines burrowing through the plant's leaves, or cottony balls on the underside of the plant, that plant should not be purchased. Those leaves are hosting various bugs, most likely a leafminer[1] or cottony scale[2], respectively.

Most importantly: check the roots. This means you're going to turn the plant (carefully!) upside down and slip the root ball from the container. You wouldn't buy a car without looking inside, would you? You need to inspect the plant's roots, as unhealthy roots mean an unhealthy plant. The blooms and leaves are not going to tell you the whole story. If there's a mat of roots extending from the drainage holes forming on the outside of the container, not only are you most likely not able to pull the container off without damage, that is not going to be a plant you want to buy.

This is what a healthy plant root system looks like: milky white, succulent, unbroken. If a large portion of the plant's roots look brown (not dirty, but actually colored brown) dried out or moldy, they are unhealthy and the plant should not be purchased.

If you see the roots circling the bottom of the container in a thick mass, that plant should be avoided, as well. If it's just beginning to circle, that may not be a problem. Here is an example of what to avoid. Don't believe that you can loosen the roots with your fingers and the plant will survive. The plant's roots will go back to circling - it's been trained to do so. Also, you shouldn't roughly handle a plant's (especially a new, young plant) root system.

The tips of the root contain the most important part of your plant: root hairs. Root hairs develop at the tips of the growing root increasing the absorption surface area. They are delicate extensions of the root, easily broken off. The root hairs are chiefly where minerals - the food - enter the plant. As the root grows through the soil, the older portion of the root "hardens" with a substance called suberin, making it impervious to water and CO2. They become a stabilizer for the plant. [3] So you can see how important for further growth the tips are!

How to put that new plant in the ground

It's generally accepted by those who know that the WIDTH of the hole is essential.[4] The hole should only be as deep as the plant's container, but at least twice as wide as the plant's width. If the flare (where the plant's stem/trunk meets the root ball) is above the soil level, that's alright, and in many locations is recommended, especially with trees.[5]

Focus on how wide the hole is. The old adage, "never put a ten dollar tree in a two dollar hole" still rings true. The more you loosen up the soil where the roots will branch out, the healthier the plant will be. There's been some controversy about amending the individual planting holes. Clearly, amending the entire planting bed is ideal.[6]

If you are planting a tree, however, which aren't always planted in prepared beds, Texas A&M Horticulture department says to allow the tree to grow its roots in NATIVE soil. Don't fill the space around the root ball with a bag of compost, in other words. The reason is this: the roots grow rapidly in the loose soil then come up against the hard, native soil. If you're like me with compacted clay, you can actually get a "vase" effect. The roots will circle in the loose backfill and not radiate outwards as they should. [7]

Other considerations: if you are buying a large plant where the roots are wrapped in landscape fabric or burlap, you should remove the burlap from the top third if the soil is poor. Any synthetic material should be completely removed. Always cut any twine or nylon rope that is holding the fabric in place once the root ball is in the hole. This prevents the roots from breaking apart or being otherwise damaged in transition. If there is a wire cage around the root ball, use wire cutters to snip it away. Pull the wires back (while wearing gloves) as much as you can. It is not necessary to remove them from the hole. It is necessary to remove any bindings around the base of trunk of the plant, as it can act as a tourniquet and kill the plant, known as girdling.[8] I've personally lost a tree due to the previous homeowners leaving nylon cording around the trunk and burying the tree deeply enough that I couldn't detect the problem. The tree died back almost entirely within two years.

Any pruning done at planting should ONLY be done to remove dead or damaged limbs. Texas A&M does not recommend removing a third of the growth to slow transpiration as previously thought by horticulturists. (Transpiration is the evaporation of water from the plant's surface, namely the leaves. This is in order for the plant to transfer carbon dioxide. In hot weather, it causes some large leafed plants to wilt.)[9]

Another factor that is often ignored, is how far apart plants should be spaced.

Spacing your plants for optimum growth

It's hard for new gardeners to understand that patience is rewarded in gardening. Most new landscapes are designed to make the homeowner feel like they've gotten the most bang for their buck, with little regard for how overgrown the landscape will be in a few years. For those of us that don't particularly enjoy digging up the majority of the landscape and dividing all of the plants every two years and making new plant beds... Actually, that sounds exactly like me. But most people don't want the hassle. In which case, don't over plant!

If a plant grows 4 feet wide, you wouldn't plant a row of them with only 12 inches between them. Aside from the plants being unable to reach their full potential, you also can face problems with disease and pests, as the roots won't have enough space to grow leaving the plants weak and open for infestation, or from lack of air flow, which can lead to a multiplicity of diseases. How ever far apart the plant's width is, you can shave a few inches (say, two or three) to get a slightly more compact look with your plants, but you should definitely stick to the guidelines. If the plant grows to two feet wide, leave 22-26 inches between the plant and other plantings.[10] If you are making a hedge of shrubs, you can knock off up to a third of the width. Example: a Japanese boxwood (Buxus microphylla) will grow to 48 inches wide. If you wanted a solid hedge, by reducing the width by a third, you can now space each plant by no less than 32 inches in between each shrub.[11]

Now that your plant is in its hole and you've gently returned the backfill, do NOT stomp on the soil to "settle the plant." I've gasped and clutched at pearls I'm not even wearing when I've seen neighbors do that. Don't forget what you've learned about the delicate root hairs of your new plant! To settle the soil and remove air pockets, GENTLY WATER the soil. Water it slowly to avoid run off, and add more soil if needed. Do not make a ring around the plant with a raised ridge - the old mindset was it would encourage a pool of water to remain with the plant. Cheap watering, if you will. A gentle slope from the plant base down to the garden bed is fine and keeps water from accumulating at the base, which can lead to disease.[12] Wet trunks/stems are unhappy plants!

Allow your plants room to grow, and room for you to maneuver between each. And as always, mulch those beds once your plant is installed!

Next post: we'll discuss watering habits and conservation.

Labels: , , , ,