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Trees and Shrubs

by Sharon Morrisey, horticulture agent in Milwaukee County

Tu-BShevat-tree-planting-by-Canopy-Photos-jpgFall is a great time to plant trees and shrubs. Warm soil encourages root growth and the cool air reduces the demand for water. It is said that the planting is the most important 10 minutes of a tree’s life. Years of scientific study have produced improved techniques, so follow these instructions closely.

  1. Find the root flare first. It’s that place at the base of the trunk where it widens before going into the soil.
  2. Remove soil from the top of the root ball, if necessary, until the flare can be seen.
  3. Measure the depth of the root ball after finding the flare.
  4. Dig the hole no deeper than this, trying not to disturb the dirt at the bottom, so the tree will not settle later and become too deep. Make the hole two to four times wider than the ball and gently sloping.
  5. Cut off the container, if there is one. Cut away the wire basket if it’s a balled-and-burlapped plant.
  6. Gently roll it into the hole without holding it by the trunk. Now, cut away as much burlap as possible without letting the root ball fall apart.
  7. Fill the hole halfway with the same soil that came out of the hole. Do not amend that soil. Otherwise, the roots will stay in that soil, growing around and around, instead of moving out into the surrounding soil.
  8. Do not stomp on the soil. Instead, fill the hole with water and allow it to settle before continuing to fill the hole.
  9. Water again.
  10. Form a rim of soil around the outside edge of the hole to hold the water.
  11. Cover the rim and root ball with 2 inches of shredded bark or wood chips. Do not allow the mulch to touch the trunk or the bark will rot and kill the tree.
  12. On slopes or windy sites, use one or two stakes pounded into the undisturbed soil beyond the root ball. Loosely secure the tree trunk to the stakes using webbing with grommets made especially for this purpose. Do not use wire or rubber hose, since these will damage the bark. The tree should be able to sway back and forth because this actually strengthens the trunk.

 

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Beyond the Blooms

by Jess Wickland

When you think of landscaping or putting together a small flower garden, many people don’t think past the flower colors and bloom times. However, there are many different aspects that plants provide that will increase interest in the garden, whether it’s seedheads, or different leaf textures, or (my favorite) fall berries and fall color. When the green foliage bursts forth in spring and gives life to the boring winter landscape, I often breathe a sigh of relief. And while flowers do provide plenty of color in the landscape and often leave me giddy with excitement over their blooms, nothing can compare to the breathtaking yellow, orange and red hues of a sugar maple tree in the fall.

Speaking of blooms, there are two shrubs that wait to hold their flowers until almost everything else has gone dormant for the season: witchhazel and seven-son flower. Witchhazel is a native shrub that grows quite large — almost 15 feet tall — and waits until October to send out its spiderlike yellow blossoms. Many times, the blooms occur as the shrub’s foliage has changed to the bright yellow color, or has dropped off already. Seven-son’s fragrant flowers blooms white in late September or early October, but perhaps the best show isn’t the blooms, it’s the pale red calyces that appear after the flowers have dropped off. This is also a fairly large shrub, growing to 15 feet tall and wide as well, and grows best in part shade conditions.

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The bright red berries of the Hawthorn stand out against the frozen branches

Many shrubs get berries as well, clinging to the branches and giving the landscape splashes of color throughout the fall and winter seasons. I always enjoy watching the hawthorn berries develop and change color in late summer. The red berries aren’t often eaten by birds in summer (they’re too busy devouring the serviceberries), and persist into the winter. After a fresh snowfall, I enjoy photographing the vibrant red berries blanketed by the glittering snow. An added bonus: hawthorn trees have a variable fall color, ranging from orange to red to maroon. Another fantastic red berry is found on Ilex shrubs: holly and winterberry. While holly are a little more finicky about growing conditions (though it can be done!), winterberry are tough shrubs that wait until the rest of the landscape is dormant for their moment to shine. In fall, clusters of bright red berries cling to the upright branches. They are offset by the yellow fall color of the shrub. Both holly and winterberry look like a picture off of a Christmas card after a new snowfall.

Chasing fall color throughout the state used to be my grandparents’ favorite thing to do in October, and I think I inherited that gene from them as well. I can’t believe the different shades of red, orange and yellow that erupt as the daylight hours get shorter. I can’t wait to go outside to see what I might capture on my camera’s memory card. Perennials aren’t just for flowers anymore, either. Gillenia trifoliata, a native perennial commonly known as Indian Physic, isn’t very showy throughout the summer. The green foliage set underneath the star-shaped white flowers may cause a passerby to glance at it a second time. In autumn, however, the foliage changes to a pale orange that gives the plant a whole new look. Mukdenia rosii also changes from emerald green to dark red and even maroon, rivaling its cousin, Heuchera, in color wars.

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Fothergilla blazes it’s colors during Fall

My favorite shrub for fall color is Fothergilla. While the fragrant white spikes of flowers and robust foliage (tinged just a hint in blue-green) are attractive, I haven’t met someone yet who didn’t fall in love with it in the fall. The foliage is much the same as a sugar maple, keeping us guessing as it changes from yellow to orange to red. It’s like watching a 4th of July fireworks show; many people “ooh” and “ahh” at the beauty cast by this wee shrub (the dwarf species only reaches 3 feet tall and wide).

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The familiar sugar Maple leaves

As you may have guessed by how much I’ve brought it up, my favorite tree for fall color is the sugar maple. Serviceberry isn’t far behind because although the berries are long since picked off by hungry robins and cedar waxwings, the fall color still rivals the maple in terms of orange and yellow coloring. An interesting plant for fall color is the larch, or tamarack. It’s a deciduous evergreen, meaning it has needles, but sheds them each year. The golden yellow needles in fall are gorgeous, especially near the end of the day when the sunlight hits them just right.

I hope I’ve inspired you to think beyond the blooms, and try to plant a few trees, shrubs or even perennials

Growing Pine Nuts

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Yummy pinyon nuts from P. edulis

Who else loves pine nuts on salads? We live in Wisconsin where we have tons of pine trees, so why not just harvest our own, right? Uh, no! Turns out that the most famous variety (pignoli) comes from the Italian stone pine, Pinus pinea, a handsome umbrella-shaped tree that is native to the Mediterranean.

Dr. Peter Del Tredici, the director of living collections at Harvard University’s Arnold Arboretum, said the best bet for our cold weather climate is P. koraiensis. It is the source of those ubiquitous Chinese pine nuts, and it is a very tough character, able to withstand high winds and temperatures of 20 to 30 below. But before you go rushing out to plant a few, bear the following in mind.

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Cones from P. koraiensis

Nut-bearing pine trees tend to be slow growers, and though grafted plants might bring your wait for the first nuts down from 15 or 20 years to something more like five or six, it’s going to take a good long time before you see much of a crop. When it comes, the crop will be encased in extremely hard shells. The shells will be tightly clasped in the cones, and the cones themselves will be well fixed to the upper branches of the trees, from which you must wrench them at the appropriate time. (You can’t wait for them to fall of their own accord; by that time the blue jays and squirrels will have beaten you to the nuts.)

Has Dr. Del Tredici ever harvested nuts from the well-established specimens at the arboretum? No, he said: “The cones are unbelievably sticky, for starters — just to handle them is a commitment.”

Planting the trees is a commitment, too, of space as well as time. Though our pinyon-nut bearing Southwestern native. P. edulis, can take bush form, and some P. cembra cultivars are modest in size, P. pinea is a big tree, and P. koraiensis is huge. Dr. Del Tredici saw some in China that were more than 100 feet high.

Pruning Water Sprouts

by Sharon Morrisey, Milwaukee County consumer horticulture agent

apple-watersproutsAs a general rule, pruning of woody landscape plants should not be done in midsummer. The one exception is water sprouts on fruit trees, particularly apples and crabapples. Both are in the genus Malus and have a greater tendency to produce water sprouts than most other genera. Water sprouts form in response to pruning out large, diameter branches.

hqdefaultIt has been shown that if the removal of water sprouts is delayed until late July or early August, fewer new water sprouts will form. If pruned out in early spring when all other pruning is being done, more water sprouts will be stimulated and a vicious cycle begun.

Water sprouts are branches that grow straight up from a larger-diameter branch. They grow very quickly and arise from latent buds buried deep inside the larger branch. The sprouts push through the outer layers of wood and bark.

As they grow taller and thicker, they become top heavy. Since they have no real connection of the branch, summer and winter storms can blow them over, and in the process, break the branch they are growing on. These sprouts also look awkward and out of place.

To avoid having to prune out large branches, begin developing the structure of trees when they are young so you remove only small branches.

Black Walnut Conundrum

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Leaves and fruit of Black Walnut

Black walnuts have a long history of cultivation on American farms and, to a lesser extent, in gardens all over the East and Midwest. They are beautiful trees, with upright trunks and wide canopies. They bear delicious (though hard to crack) nuts, and they are very valuable as timber trees — a single straight trunk can be worth thousands of dollars.

Unfortunately, black walnuts are not completely garden-friendly. The extensive surface roots compete with anything planted over them, the thick leaf cover produces dense shade, and all parts of the tree exude a chemical called juglone, which inhibits the growth of a great many plants.

Vegetables in the solanaceous group — tomatoes, peppers, eggplants, and potatoes — seem particularly sensitive to joglone, as are many perennials, including columbines, peonies, and chrysanthemums. Hydrangeas appear to hate juglone. So do rhododendrons and azaleas, lilacs, and lilies. Ditto pines and birches, apples, and blueberries.

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Stately Black Walnut with beautiful over-arching canopy

Because juglone-laden feeder roots extend far beyond the tree’s canopy, and juglone-containing leaves and nut hulls also tend to get spread around, none of the plants listed above is likely to do well unless it’s at least 50 feet away from the drip line of a black walnut and 100 or more feet away from the trunk.

So what’s left? Quite a lot, really. Kentucky bluegrass and black raspberries actually seem to thrive when planted near (but not under) black walnuts. If the soil drainage is good and other growing conditions are right, gardeners have also had success with cucurbits (squash, melon, and cucumber), as well as beans, beets, and carrots.

The list of possible flowers is longer, starting with spring-flowering bulbs (except crocus) and woodland wildflowers such as Jack-in-the-pulpit, sweet woodruff, and cranesbill. Many hostas appear to be up to the challenge, and asters, day lilies, coralbells, and Siberian iris are also likely bets. Euonymous usually does o.k., and so do Japanese maples, viburnums, redbuds, and hemlocks.

One warning: As the recurrence of words like “seems” and “possible” suggests, these pros and cons are based on observations, not controlled experiments. And to complicate matters further, the amount of juglone in the soil can vary considerably, depending on such factors as soil type, drainage patterns, soil microorganisms, and the age of the tree.

So, if there’s something you’re dying to try under a black walnut, try it. But watch carefully. Affected plants will quickly show signs of stress and should be moved before they start dying, too.

Do You Feed Your Trees?

tree-970850_960_720Here’s a question that tends to divide folks right down the middle. When it comes to the wisdom of feeding trees, expert opinion is sharply — in some cases acrimoniously — divided, but the weight of modern practice is increasingly in favor of the dictum that less is more.

A small amount of fertilizer is fine. It will help compensate for the absence of natural fertility that tends to distinguish lawns (where all the leaf litter gets raked up and there is no understory to speak of) from woodlands (where the trees are nourished by lots of decayed plant material).

Fence_and_tree_lined_lawn_Little_Laver_Road,_Essex_EnglandBut before you go out and buy tree food, remember that the small amount needed is likely to be already present as a by-product of fertilizing the lawn. Once you get into adding more than that, it’s likely you will do more harm than good — if you do anything at all. The harm comes because fertilizer pushes the tree into making lots of tender, soft growth. It’s lush, it’s green, it’s very impressive, and it’s also highly vulnerable t insect attacks, climate stress, and the myriad fungus diseases that would be thwarted by tougher tissue.

The doesn’t-do-anything-at-all situation results from putting the food where the tree can’t get at it. Most of a tree’s feeder roots are in the top 10 to 18 inches of soil, and most of them start near the out edge of the canopy (the drip line) and spread outward from there. That means using an injector to put the eats down deep is not going to do much except pollute the groundwater. And spreading the tree’s meal close to its trunk will be just as fruitless.

The bottom line: keep feeding to a minimum unless the tree is in a container where it cannot possibly find nourishment on its own. And if you do use fertilizer on a landscape tree, spread it in a wide band that works out from the drip line.

Pioneer Chinese Apricot

by OCMGA Master Gardener Tom Wentzel

UntitledThis photo was taken on April 17. I have 2 of these trees and they are both loaded with blossoms.   This variety is hardy to zone 5, so we are on the north edge of its range. In general, apricots are one of the first fruit trees to bloom which makes them susceptible to late frosts. These trees are growing up against my house as an espalier. This gives them a little extra protection. Still, I do not get a harvest every year. The taste of the fruit is amazing. You do need to keep an eye on them because they ripen very quickly.

My next crop is peaches. It’ll be a couple weeks before they bloom. The variety that I have is Contender, which is the most common variety in this area. This is a freestone variety that is hardy to zone 4. I do get a harvest yearly from the trees that I have.

Don’t be afraid to give these a try. Both are self-pollinating. They are not more work than any other fruit tree. I do not spray and have not had any insect problems. Admittedly there may be a fungus starting on the peach, I keep an eye on that.

Not many of the apricots or peaches make it into the kitchen, they get eaten on the way.