hedge tree type

Asked November 15, 2017, 3:05 PM EST

Looking for a 80' long hedge to screen the neighbors new construction. My research seemed to point me to Green Giant arbs but I have not found any at my local wholesale nursery's. I have found some Leyland Cypress and Incense Cedars in 5-6'. and am leaning towards the cedars at 7' on center in a north south line. Are there any issues with either of these two species for bugs or scale in this county? Is there a preference or recommendation from OSU? I am looking to duplicate the Airport way entrance with Cedar and to the west of that deciduous trees (redbud, maple, or Tupelo) to the west with shrubs around them- any apparent down sides to this plan? I have about 10 honeybee hives on the lot and the nurseryman told me that the Linden that I wanted is toxic to bees in certain conditions-is this a valid concern since the bloom time is perfect.

Clackamas County Oregon

3 Responses

Incense cedars and arborvitae both make good privacy hedges, they're evergreen and attractive. Both have aromatic oils and insects are usually not a problem (hence cedar chests to preserve linens).

Incense cedars (Calocedrus decurrens) Incense Cedar https://plants.usda.gov/plantguide/pdf/pg_cade27.pdf are long-lived (1000 years), native and grow about 1-2 feet per year once established. It takes a couple of years for the roots of a newly transplanted tree to grow into a new location. Well-drained soil is important for both trees, really for all trees, especially with our wet winters and springs. If water doesn't drain well from the soil, the trees can drown. Tree roots require air as well as moisture. Select a planting site where water drains away. Regular pruning will maintain shape and keep the trees at a good height. 6-8 feet is recommended between trees for a hedge.

Arborvitae "green giant" (Thuja standishii x plicata 'Green giant), Green Giant Arborvitae https://www.arborday.org/trees/treeguide/TreeDetail.cfm?itemID=779 grows 3-5 feet/year and can grow to 50-60 feet tall. Regular pruning is necessary to keep them in scale with your property. Arborvitae likes moist well-drained soil. In our area summers have little rain and so Arborvitae need summer watering to maintain moisture. There are other arborvitae that are smaller and slower growing.

Your deciduous choices should work well. Redbud (Cercis canadensis) with brilliant magenta flowers in the spring and golden fall color is a very attractive tree of 25-35 feet. There is a native redbud 7-23 feet tall, often with multiple trunks. Maples (Acer sp) have good shape, attractive leaves and great fall color, and many choices for size, shape and color. They can develop root rot from various fungi and need well-drained soil. Tupelos (Nyssa sylvatica) are known for great fall color and grow to 30-55 feet high with a spread of 20-30 feet at maturity. Lindens (Tilia cordata) are beautiful trees that grow to 50-60 feet and have fragrant flowers in summer. However, there is an issue with the trees and bumble bees that does not seem resolved at this point. The Mystery of the Dead Bumblebees and the Linden Trees https://www.nytimes.com/2017/09/27/science/dead-bumblebees-trees.html. We had a major die-off of bumblebees in Wilsonville, but that was caused by spraying the tree with nicotinamide based insecticide to which bumblebees are very sensitive. However, there have also been bumblebee die-offs in lindens in England without spraying.

Thanks Ann for your quick reponse. As I described I am unable to get the Arborvitae I prefer (green Giant) and the choice falls between the Incense Cedars and Leyland Cypress. I have read that the Leyland has some bug and scale issues but being the internet it is wide reaching. I was curious as to if the cypress has had local issues here as well as your opinion on the preference between the two species (cedars or cypress) for a fast growing hedge. I can get 5-6’ of both plants for the same cost.

Leyland Cypress https://www.arborday.org/trees/treeguide/TreeDetail.cfm?Itemid=828

Leyland cypress (Cupressocyperis leylandii) seems to do well in our area. The main downside to them is that they grow very fast (up to 4 feet/year) and tall (60-70 feet at maturity), often outgrowing their allotted space quickly. The main insect pest is Cedar and Redwood Bark Beetles in SW OR http://www.ufei.org/ForesTree/files/collected/cedar beetle.pdf, but it doesn't appear to do much damage to the trees. This chart Matching Trees to Environment S OR http://extension.oregonstate.edu/sorec/sites/default/files/Note_1.pdf

giving information on tolerance for wet soils and drought might help you with your decision.

The main way to have healthy trees is to plant the trees properly , in well-drained soil and at the proper depth (the root flare should be at or 2inches above ground level), then maintain proper pruning and watering. This article, Selecting, Planting and Caring for a New Tree https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec1438_0.pdf has information on all of that. Of course, awareness or the mature height and size - and potential demands of the trees so you make the right choice to begin with will save you money and time down the road.