Category Archives: Trees

How snow accumulation affects your landscape

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It has been years since we have to wait until the middle of January in Chicagofor the first significant accumulating snow of the year (+2″), but here we are.  It is often right after the first significant snowfall of the season that we hear from many concerned customers about the potential damage that snow may do to their trees and shrubs.  While snow is vital to the winter survival of plants and trees it can create some problems for your plants under extreme conditions.  In case you were wondering how to avoid damaging your plants this winter, read on…
  • Heavy, wet snow and ice can often cause branches on deciduous plants to bend or even break because they are frozen and brittle.  On evergreens such as arborvitae, junipers, yews, etc., which have a broader surface on which snow and ice can accumulate, branches can be stretched and bent, disfiguring the shape of the plant and causing damage below the surface of the bark that will not become evident until Spring.
  • If you are concerned about a heavy accumulation of snow on your landscape plants, carefully brush the snow aside by hand to avoid causing damage.  Avoid shaking or striking the branches with brooms or shovels as this can cause more damage than it prevents.  Bear in mind, that natural snowfall or windblown snow seldom results in plant injury. It’s usually the devices we use to remove snow that cause the most damage.  Snow that is plowed, blown, pushed into, or thrown over plants is denser than natural snowfall and tends to stick together, so as it settles, it can rip branches or snap buds from limbs.
  • Snow serves as a great natural insulator because snowflakes have small intricate spaces within their structure which are filled with air. These spaces trap air in between the flakes as they pile up. These tiny pockets of air prevent circulation, thus preventing heat from being transferred by convection.  As a result, the daily temperature penetration into the snow is minimal and plants are protected from frost and freezing conditions.
  • Snow on the ground acts as an insulating blanket of mulch that prevents injury to roots, which generally can’t withstand extreme cold. The roots of most landscape plants can be damaged when soil temperatures fall below ten degrees F.  Some perennials, whose roots are far more sensitive than woody plants, can be harmed when soil temperatures dip just below freezing. The snow cover will moderate temperatures, and once the snow melts, the moisture is beneficial to the plants.
Of course, the best solution is not to cover plants with excessive snow at all.  Avoid plowing, blowing, or shoveling over the top of your plants.  Mark your beds in Fall with posts or reflectors if necessary to make them more visible under extreme snow conditions.
Avoid piling “salty” snow near plants or on lawns.  If you choose to use ice melt products such as rock salt on your walks and drives, keep in mind that this, mixed with the snow and slush that is piled around plants, can leach into the soil and harm roots.  Plants will absorb these contaminants in the Spring which may cause die back and even death.  If you must “salt”, use one of the more environmentally safe products such as calcium or magnesium chloride or an ordinary, inexpensive garden fertilizer, sand, or kitty litter mixed with equal parts of “safe” salt.
Consider these plant care tips now before the snow really starts to fly as it is easy to forget them in the throes of one of Chicago’s blizzards or ice storms.  By taking extra care now when removing snow or melting ice you can keep your trees and shrubs safe from snow injury and you will find them to be more hearty and healthy come Spring.
Kevin Block
RLA
Certified Arbotist

Favorite Plant Series: Taxodium distichum

One of my favorite trees is Taxodium distichum, or Baldcypress (also Bald Cypress). Once you recognize it, it’s always a delight to see. Baldcypress has the rare distinction of being a stand-out tree in virtually any type of setting or application. Alone or in groups, in formal or naturalistic settings, urban or wild, Baldcypress often becomes the focal point of a well-thought-out planting design. Part of that distinction arises from the fact that it has yet to have been overplanted – at least in Chicagoland-area landscapes – and is often greeted with delightful curiosity by the uninitiated.

While such a versatile tree, there are limitations to Baldcypress’s use given its eventual size and habit. Growing 50’-70’ by 20’-30’ wide, Baldcypress takes on a mostly pyramidal shape. While tall, it may not perform as a traditional shade/canopy tree for many years, if at all. Although the northernmost portion of Baldcypress’s native range is technically southern Illinois, the tree does quite well in northern Illinois and southern Wisconsin. Baldcypress does well in wet, dry, and well-drained soil conditions and is relatively salt-tolerant.

Leaves in springtime are a bright yellow-green and eventually turn a medium sage green come summer. The leaves turn orange-brown in autumn and hold for a while before dropping as winter approaches. Interestingly, Baldcypress (along with its cousin Dawn Redwood, also hardy in this area) is one of only a few varieties of cone-bearing trees that lose its leaves in the winter. Seeing the small ½” – 1” cones Baldcypress produces adds to the surprising nature of the tree. The reddish-brown bark with a fibrous nature can be striking in winter.

Famed modernist landscape architects such as Dan Kiley and Peter Walker used Baldcypress in formal, urban settings (see Fountain Place in Dallas and water features outside UBS Tower in Chicago – see picture). Locally, the Heritage Garden at the Chicago Botanic Garden features a pruned baldcypress hedge, now several decades old. Such formal cues can be also adapted to residential settings, as well as using Baldcypress as a standalone specimen tree or loose grouping. With such versatility, Baldcypress might be the “problem solving” tree for your landscape.

Taxodium form

baldcypress_chicago

Bald cypress in the landscape

Up close of the leaf

Written by Ken Horinko, ASLA
Landscape Architect

Why Leaves Change Color

fall maple

During the growing season, chlorophyll, essential for photosynthesis, is continually being produced and broken down and leaves appear green. As night length increases in the autumn, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids (responsible for orange, yellows and browns in things like bananas and clementines) and anthocyanins (responsible for reds and purples in items like cherries and berries) that are present in the leaf are then unmasked and show their colors.

Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells.

A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays. During these days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions-lots of sugar and lots of light-spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson. Because carotenoids are always present in leaves, the yellow and gold colors remain fairly constant from year to year.

The amount of moisture in the soil also affects autumn colors. A late spring, or a severe summer drought, can delay the onset of fall color by a few weeks. A warm period during fall will also lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights should produce the most brilliant autumn colors.

Some of my favorite places to enjoy the onslaught of fall color?  Visit now and often over the next few weeks and watch the marvelous display.

Independence Grove (shown in photo above)

The Morton Arboretum 

 

Watering Guidelines – new trees and shrubs

During the spring we generally receive a sufficient amount of moisture.  Spring to summer is probably the most critical transitional period because moisture levels can drop quickly and soil moisture availability rapidly declines.  This situation can be exacerbated by overly hot and windy conditions.

When plants start to show signs of stress by wilting permanent damage to the vascular system may have already occurred.  Prevention is the key; therefore we have prepared the following guidelines on the basics of proper watering procedures.

Time of Day to Water

The BEST time to water is about 3 a.m. to 10 a.m.  At this time the air is cool and very little evaporation loss occurs before the water reaches the ground.  When the sun rises and the air warms, the liquid quickly evaporates from the leaves.  Watering early in the evening encourages fungal infection (fungal infections thrive in cool wet conditions); watering in the heat of day is bad because much of the water evaporates before reaching the ground.  This accelerates buildup of soluble minerals in the soil that over along time can be ruinous to soil health.

Accurate Measuring

When you water, water deeply.  This means water for a long time, allowing the water to soak into the ground.  Ideally, you should provide one inch of water with every soaking, but not more than once per week.

Remember to take rainfall into consideration when monitoring your watering. Use a rain gauge to monitor the amount of water your landscape receives from rainfall and your irrigation system (if applicable).

Be careful…you can over water your plants!  Roots need both water and oxygen to thrive.  Over watering can kill plants because constant moisture suffocates the roots, thereby causing them to die and rot.  Inspect the area BEFORE watering by tunneling with a deep root feeder or stake.  If the soil is dry on top, it might still be moist underground and not need water.

Newly Planted Trees

When watering newly planted trees, remove the nozzle from your hose, wrap the hose in an old bath towel  (so it will disperse the energy of the spray) and set the hose at the base of the tree.  Water the area at a low pressure every other day (45 to 60 minutes) for 3 to 4 weeks, based on your soil conditions.  Make certain to change the position of the hose to water evenly.

Newly Planted Shrubs

Shrubs can be watered similarly to trees except the time frame drops to 10 to 15 minutes each.  Avoid watering foliage, most plants DO NOT like being watered from above because moisture build up on leaves encourages fungal problems.

For more information there is a great article by the University of Illinois Extension.