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Mike Epp's Landscape Gardening Weblog
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Installation
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Installation (Let’s get busy) As mentioned before, deal with the “big stuff” first. If “hardscape” construction is in the plan, such as walls, walkways, decks or patios, these should be installed first. Hardscape construction will require easy access for machinery and materials. Heavy construction will also create a big mess in the beginning. The planting and mulching stage is the finish after which you’ll want to hose off the walkways, water the plants and sit back to enjoy your work with a tall icy beverage. Although, of course, it is critical that these features be correctly installed, actual construction details are not within the scope of this discussion. For construction details, please consult the appropriate literature or a professional. After your hard surfaces are constructed and the finish grading is attained, it’s time to place the trees. Again, these are bigger items that you’ll want to get in place and work around for the smaller things. The number one, most critical thing to get right when planting trees is DON’T PLANT THEM TOO DEEP !!! It seems to be human nature when planting to want to get the roots down low so they don’t dry out. Particularly in heavy clay soils this is the worst thing you can do! As mentioned in the discussion of soils, heavy clay is poorly drained and can easily drown out tree roots by holding too much water. Tree roots also require good aeration as well as sufficient moisture. Too much water pushes out the oxygen and therefore can suffocate the roots. Mounding the entire bed or area is a good idea when planting trees. It doesn’t have to be an excessively high mound. A foot to 18” is sufficient. But when “spot planting” make sure the top surface of the soil ball is about 1-2 inches higher than the surrounding area. This will promote surface drainage and reduce excessive wetness around the roots.
Ground preparation In a perfect world, it’s a good idea to rototill the entire bed area that’s about to be planted. You’ll want to mix in organic matter to improve heavy clay or sand. This is an excellent time to incorporate phosphorous or bone meal into the ground which will encourage root development. But tilling isn’t always possible around the foundation of a house with telephone lines, tv cables, gas lines and other utilities. Your first step in the installation process should be to place a phone call to your local “Utilities Protection Service” to have underground lines marked to prevent cutting them. Lines that are 3’ deep are usually safe from hand digging. But with so many utilities and irrigation lines buried just beneath the sod, it’s very easy to cut lines by simply edging the beds and planting flowers. If tilling isn’t an option, simply edging the beds and adding good topsoil will improve the drainage and soil quality. The good soil can be mixed with the subsoil in the process of planting. Of course over the years the soil structure will improve by the activity of earthworms and microbes provided there’s no weed mat to inhibit this beneficial activity.
Mounding with Topsoil Bringing fresh topsoil into your planting beds is always a good idea. Even if your soil is already a good garden loam, you can raise the beds for better drainage and to make them stand out above the lawn level. An added benefit is that smaller trees will gain a foot or more in height when planted in a raised bed! Tilling in compost will raise the beds somewhat, but adding topsoil to get the beds up 1’ or so will better enhance the appearance and drainage of your planting bed. When buying topsoil you’ll probably want to get it in bulk to save cost. But be careful what you get. You want a rich dark topsoil, not fill dirt! If the pile is full of hard, heavy chunks it’s probably just more clay. Some soil suppliers have pulverized and screened topsoil. This will cost more but is very easy to work with. Otherwise, a clean alluvial topsoil dug out of creek beds will be sufficient. Just be sure that you are not buying weeds! Specify that you don’t want weed roots and weed seed brought in which will obviously increase your maintenance later.
Spacing plants As mention previously, you’ll want to plant the trees first followed by the larger shrubs. It is critical to get the larger features spaced properly and then work around them with the smaller things. Generally speaking you should space plants at least as far apart as their mature width. Large shade trees should be placed 50’ apart. Of course a 50’ diameter means a 25’ radius so they should be planted 25’ from a house or property line. You can crowd a fence or property line somewhat but be aware that any part of a tree that crosses your neighbor’s property line belongs to your neighbor. He can prune it as he sees fit. You can also crowd a wall somewhat since plants will tend to grow toward the light and not toward a wall. But be very careful not to crowd too much or you will be planting a problem for the future! Coniferous (cone bearing) trees such as pine and spruce are typically planted 12-20 feet apart to create a screen. A good average spacing is 15’. At this spacing they will grow into each other eventually forming a nice screen or windbreak. Remember, staggering the planting rather than straight rows will look more natural and give better results in the long run.
Planting (Don’t dig a $5 hole for a $100 tree ! ) The planting hole should be twice as wide as the root ball but no deeper. It’s a good idea to dig the hole wider than the root ball to loosen up the soil around the ball providing the new roots with a soft medium to begin growing into. While a little organic matter mixed with the backfill is a good idea, it’s not necessary to put a lot of potting soil or peat moss into the hole as the roots will have to adapt to the existing soil if they are going to survive in that location eventually. At the risk of being repetitive here, I’d like to emphasize that it is critical that the hole not be dug too deep! Digging too deep will cause the tree to settle when the bottom soil compacts resulting in the ball being too low. Planting too deep in heavy clay soil is the number one killer of trees in the Midwest. Clay soil is poorly drained so it’s better to plant an inch too high than an inch too low. Planting slightly higher than the surrounding soil level allows the surface water to escape and not puddle around the tree. Excessive water in the root zone will displace the air in the soil and cause rotting of the roots. Should I remove the basket and burlap? NO. You’ll find mixed opinions on this topic. Some say the roots might be “strangled” by the basket when they get bigger. In my experience, I’ve never seen that to be the case. I’ve seen trees that were “heeled-in” to a mulch bed in a nursery for 20 years in a steel basket. They rooted into the ground and are growing fine. If you’ve ever noticed a tree trunk growing in a wire fence row, the trunk will grow around the wire. That’s why lumber mills won’t take a tree that’s been growing in a fence row. Their saw blade might be ruined when it hits the wire that’s embedded in the tree trunk. Similarly, the roots will grow around the basket wires and keep on growing. More damage can be done in removing the basket, burlap and tying rope by loosening the ball. Don’t worry about cutting the burlap or natural rope. These materials will rot away in time. Plastic burlap or polyethylene twine, on the other hand, should be removed. These materials should never be used in the nursery in the first place. If you are buying plants from a nursery that has plastic burlap or twine on the roots I’d question dealing with that nursery in the first place! It is critical that the root ball stay intact. Loosening any of this material could cause the ball to shake loose or the tree to blow out of the ground. If you choose to cut the root ball covering material you MUST then STAKE the tree.
Staking Should you stake your trees? Maybe. While a larger “bare root” tree will be “top heavy” and need to be staked to keep it from blowing over, a tree with a large, heavy root ball will probably keep itself upright with no staking. The modern thinking is that staked trees will rely on the stake for lateral support and fail to develop stabilizing roots. If the tree will hold itself upright it’s best to not stake it. A stake can be added at a later date if the tree begins to lean. Many other commonly held “rules of thumb” in gardening are being rethought. It used to be common to paint black or gray paint on trunk wounds or pruning wounds. The current thinking is that a tree will heal itself better if the wound is left open to air and sunlight. It makes sense. We wouldn’t paint a wound on our arm, why should we paint a wounded tree? Even the unsightly white color of a fresh pruning cut will quickly fade to gray and look natural. Hey………doing nothing is low maintenance!
Are you a Mulchaholic? While mulch is the icing on the cake of a new landscape installation, in my opinion it’s way overrated. There are far more types and colors of mulch available today than is necessary. You’ll see bags of cedar, cypress, nuggets and even colorful gravel. There is so much mulch flying around in the spring that everyone is in the mulch business from the fund raisers to the gas station. It’s really not surprising that there is so much interest in mulch. A nice clean layer of fresh smelling mulch is probably the most highly noticeable aspect of a new landscape installation. But it was never intended to be the permanent, end result of your landscaping efforts. I’m sure you’ve seen the large expanses of mulched beds with no plants in them or just a few widely spaced trees around which mulch is applied annually. This is poor design from both a maintenance and an environmental sustainability standpoint. Why not cover these beds with a woody or perennial groundcover which spreads and chokes out most of the weeds? Mulch is meant to be a temporary means of holding moisture in the ground and eliminating weeds from a newly installed bed. It’s not meant to be a permanent groundcover. A mulch is anything used to cover and insulate the ground. Shredded bark is normally used because bark will resist decay. You should not use uncomposted wood chips because the raw wood will decompose quickly and rob nutrients from the soil in the decomposition process. Mulches have been used for ages to condition the soil in vegetable gardens. Gardeners have used materials ranging from old shredded newspaper to wheat straw or compost as a mulch. Your mulch should be an organic material so that when it eventually decomposes, it can be incorporated into the soil to improve the soil structure. Rototilling an old decomposed layer of mulch into the soil is a great way to improve the soil structure. But this also occurs naturally over time by the action of earthworms, freezing and thawing and percolation of rain water. This is one of the reasons I dislike the use of weed mat of any kind. It interrupts the natural mixing of the soil column. But I’ll say more about that later. Shredded bark or pine needles will provide a nice, clean uniform appearance to the entire newly planted bed area. But remember that its main objective is to insulate the soil and create a good growing environment for the newly transplanted plants. After several years, your garden beds should be designed to fill in with plants covering the ground to eliminate weeds. Weeds grow in the open spaces. The objective should be to fill those spaces with desirable plants. In time the open areas to be mulched should be small areas between masses of plants. The type of mulch used should depend upon what is naturally occurring and available in your area. If you live in Arizona, that might be sand or gravel. In Georgia where there is a predominance of pine trees, a pine needle mulch is appropriate. In the Midwest where the natural landscape is covered with hardwoods, you should use a hardwood bark mulch. Using a local material is more sustainable, natural and less expensive. Most cities today are composting their organic waste. Mulching with this material is an ecologically efficient use of the branches and leaves that people set out by the curb annually. It’s not uncommon to see mulch reapplied every year just to refresh the color and smell. Piling on mulch every year can create a problem. A thick organic layer can inhibit the healthy interaction of the soil with the air. Piling mulch up around trees can cause the bark to rot and create a haven for insects. A two inch layer of mulch is the norm for a new installation. One inch is normally sufficient for a fresh layer over the top. Spring is a good time to redefine the edges of your beds, do a light pruning, weeding and applying a light layer of mulch to refresh the color. You can even paint your mulch for a fresh look! Actually, that’s probably a better alternative to adding a thick layer of mulch annually and suffocating your soil.
Mulching recap: Mulch is temporary 2” is plenty Hardwood bark is sufficient Don’t pile up around tree trunks Plants are your ultimate groundcover
email: mikeepp@mindspring.com |
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