February 14, 2019

Five Questions

I think everyone has had about as much cold and snowy weather as they want... I know I have. Even though it may not be nice to get outside in weather like this, it is possible to dream and look forward to nicer weather in the next few months. One of the best ways I know is to look at the garden catalogs and decide what tree or shrub you want to add to your landscape this year. It always amazes me that they can get such beautiful specimens that never look quite that good when I plant them.

Even if they may not look as good as the pictures, a variety of trees and shrubs are the foundation of any landscape can make any place look better. But the question I get most often from homeowners is, “What tree (or shrub) should I plant in my landscape?” Fortunately there is no one answer to that question or a lot of landscape designers would be out of a job, it would be too easy to make a recommendation, and everybody’s landscape would look the same.

But you don’t need a landscape designer to answer this question, just a little research on your part (remember, it’s too cold outside to do anything else!) will help narrow your search.  Remember, trees and shrubs are long term investments in our landscape so start by answering these five basic questions.

The first, and most critical question, is “Will this plant grow in my site?” First consider the plant’s winter hardiness. I know we are now in zone 5 on the hardiness map, but I still look for zone 4 plant materials. The problem is, we’re still going to get an occasional “zone 4 winter” and lose a lot of zone 5 trees and shrubs. I plant some zone 5 plants, but consider them as an experiment!

You should also consider if the site is sunny or shady, exposed or protected, soil texture and pH, and if the soil is well drained. If you're not sure what conditions a particular plant needs, ask garden center personnel or call your local Nebraska Extension office.

Another question that is easy to overlook, but it's becoming more and more important, is, “Is this a commonly planted species?” If you see a lot of one type of plant in your community, it is overplanted which could lead to problems. Overplanting one type of tree or shrub often leads to a greater problem with diseases or insects and less biological diversity in our plant communities.

Some of the best known examples of what happens with overplanting one species is the loss of American elms to Dutch elm disease, the loss of Scotch pines to pine wilt, and probably in the near future, the loss of most of our ash trees to emerald ash borer. If you are going to treat your ash tree(s), don’t start treating it/them until EAB has been confirmed within 15 miles or less of YOUR ash trees.

When selecting a major, long-term investment like a tree, I have developed Wilson’s Rule of Fives, probably because nobody else will claim it! It goes like this, “When selecting a tree to plant in an urban setting, don’t plant the same species that anyone within five blocks of you has planted. In a rural setting, avoid trees that anyone else within five miles of you has planted!” Obviously, you are not going to inventory all the trees within five blocks or five miles of you, but look for something that is different to add diversity and hopefully avoid the next “tree plague” that comes along.

A third question to ask is, "Is this plant fairly disease and insect free?" Ask what problems a plant has and how often the problem occurs. There is no perfect plant that is completely disease or insect free, but some are known to have more pest problems that could injure or kill the plant if not treated or ruin its appearance.

A fourth question is about plant size. "Is the mature plant the right size for my location or for the needed landscape function?" Many plants are planted in locations too small for them, planted too close to one another, or planted too close to a building, sidewalk, driveway or street. In these cases, it may require annual pruning to keep it in bounds which takes time and effort you’d rather use somewhere else, increases yard waste, and often changes or ruins the plant’s natural form.

On the other hand, if the needed function is privacy or shade; make sure the plant is the right height and width to achieve this. For example, for maximum energy conservation, shade trees should be tall enough to shade the wall and roof on the south side of a home. On the west side, walls and windows need shade so a smaller tree may be sufficient. 

Finally, it's time to ask yourself, "Will this plant enhance my landscape aesthetically?" Does it bloom? What time of the year does it bloom? Does it have fall color? While these are important questions, keep in mind these characteristics are usually short lived. Spring bloom or fall color may last for days up to a couple of weeks if we're lucky.

Also consider the plant’s appearance when it is not in bloom or fall color. Characteristics to consider are the mature plant’s shape, texture, and what the leaves look like during summer. Some plants are beautiful in bloom, but lack ornamental value during the rest of the season.

While there are many other questions to ask about a plant (Is it good for pollinating insects?, Does it provide fruits, nuts or berries?), these five are the most important when selecting a plant that will perform well and enhance your landscape.

For more information on selecting trees and shrubs, contact your local Nebraska Extension office.