With certain junipers, be wary of drought
I have two tree questions for you! First, we’re thinking about planting a columnar blue spruce “Iseli Fastigate” in our yard. Bookcliff’s online description says they get 20-25 feet tall and 6-10 feet wide, but Colorado State University’s recommended evergreens lists them at 15 feet tall and 5 feet wide. Can you offer any insight on the discrepancy? I live in Rifle, and I want to make sure I am comparing apples to apples before sending my husband down, and that I’m getting a tree that won’t quickly outgrow my space for it!
My second question is, I’m looking for a recommendation for a tree to plant in a non-formal row to provide a little privacy but that won’t break the bank. It does not have to be a full screen/hedge. I’m thinking more of a row of evergreen trees or juniper that is roughly 12-20 feet tall and 8 feet wide for a row. Area to cover is 40-60 feet of shared property line, north side of house, grass/sprinklers on one side. Techny arborvitaes, Wichita blue or spartan junipers, or any other thoughts you can offer?
The discrepancy in sizes is easy to explain — the “mature” size of a plant depends on how old the plant is at that time. Plants aren’t like people, where we grow to a certain size and then stop (unless it’s to grow wider!). Plants never stop growing (though they do slow down a lot as they get old). A 100-year-old plant will be bigger than it was when it was 99.
At our store we try to set “mature” size at 25 to 30 years down the road. Some people will set that size for a younger tree. I would estimate that that tree will get to the size CSU is talking about in 10 or 12 years. On the other hand, this plant will eventually get bigger than we say given enough years.
Another thing to keep in mind here is that the growth rate and ultimate size depends on how happy and healthy the tree is. A healthy, vigorous tree will grow faster and get bigger faster than one that’s just limping by.
As for your evergreen screen, you’re on the right track. My personal recommendation to people is usually to go with an upright juniper variety of some sort. They’re tough, drought-tolerant, fairly pest-free and grow faster than arborvitae. There are several varieties to pick from; you’ve hit on the two most popular in spartan and Wichita blue.
People tend to prefer arborvitae because they smell good and they’re not prickly and itchy like a juniper will be if you’re working closely with them. As I’ve mentioned, arborvitae are slower growing, so you’ll have to be more patient with them.
However, the biggest problem people run into with arborvitae is drought damage. These plants are fairly intolerant of drought, especially when they’re young. Folks notice that a portion or the entire plant just dries up. With most plants, you dry them out a little, they wilt, you give them water and they recover — maybe with some minor leaf burn or dieback. With arborvitae, you cross that line of drought and the plant is just not coming back. Now they don’t want to live in a swamp, but you have to be pretty careful for the first two or three years that the soil has some pretty consistent moisture.