Evergreens make up a large portion of our landscapes. Some selections tend to be embraced, overplanted, and can lead to insect and disease pressure. Also, care and pruning can enter into the selection.
So where do we start with considering evergreen trees or shrubs for the landscape. Three words: DO YOUR RESEARCH!!
The following is a list of topics to consider as you research plant selections.
1.) Ph is a very important when selecting evergreens. Many require a Ph as low as 5.5. Most do not thrive in an alkaline soil above 7.5. This Hemlock struggles from growing in a Ph of 7.6 as opposed to thriving at 6.0.
2.) Drainage has a large impact on the success of evergreens. Generally, most evergreen trees and shrubs prefer moist, well drained soils. If the same trees are planted in poorly drained soil, they will struggle like these Norway Spruce.
3.) Zone hardiness and preference should be considered. The forests in northern Ohio begin to transition from simply deciduous hardwoods to a mixed forest of deciduous and evergreens.
As we move north across the Great Lakes into Canada, evergreen trees occupy much more of the forest as it becomes a Taiga biome, which is predominately evergreen, conifer forest (cone bearing).
As our climate gets warmer, many of the evergreens we have traditionally planted may begin to experience stress due to higher summer temperatures, drought, excessive water events, and more moderate winter temperatures.
Interestingly enough, evergreens tend to thrive where there is elevation variation and cold temperatures, like the ones at this ski resort located in Mansfield which tends to be a frost pocket.
Surprisingly, they are not the only ones who like this condition!
Stressed trees tend to be more disposed to insect and disease pressure. An example is the Blue Spruce with symptoms of Rhizosphera.
4.) Maintenance can enter into consideration. Many of our evergreens can be pruned into shapes. The landscapes of the past included bowling balls, columns, spirals, pom poms, and even letters or numbers.
The tendency now is to allow evergreens to be selected based on growth habit that requires less intensive maintenance as with these Alberta Spruce. But some homeowners and landscapers still like their nice, manicured shapes.
5.) Growth habit is a consideration in itself. Some conifers can be upright and triangular. Other growth habits can include compact growth habit, weeping habit, or prostrate habit.
6.) Foliage color can be another consideration. From blue green, to variegated to bright yellow, leaf color is a consideration.
7.) Texture is another consideration. Broadleaf evergreens can provide a coarser texture while needled evergreen can tend to be a softer look.
8.) Genus and species as well as cultivars are important. Many of our narrow-leaf evergreens can include Spruce,
Fir, Pines, Junipers, Chamaecyparis, and Arborvitae.
Broadleaf evergreens can include Boxwood, Holly, Azalea, Rhododendron, and some evergreen Magnolias.
But not all grow in all parts of Ohio. And just because they are suited or recommended to grow now, doesn’t mean they will be suitable in 20 years.
In addition, some plants are prone to diseases like this Austrian Pine. Others can be very tasty to wildlife especially deer, who will browse as far as they can reach.
Deer love Japanese Yew!
The take home message is “Do your research!” One good site that can be a resource is Missouri Botanical Garden:
But don’t give up on Evergreens. Many evergreens can still survive and thrive in Ohio if given the right conditions.