I’d like to install an arbor next to a rose bush. How far away should I put it to avoid injuring the plant? -Rachael
To keep from harming your rose bush, you’ll need to locate the arbor poles where digging won’t disturb the plant’s roots. To do this, you’ll need to know two things:
The size and depth of the post holes depends on the type of arbor and how it’s installed. Poles with poured concrete reinforcement around them might need a hole as big as 2-3 feet deep and 1-2 feet wide, while a lightweight soil mounted arbor might only require a 12” diameter hole.
Plant Root Size
You’ll also need to know the approximate size of the root ball of the existing plants near the arbor location. Roots can vary depending on the plant, and unless you want to do some careful exploratory digging, you’ll have to make an educated guess. There are several ways to estimate the size of a plant’s root ball:
- Trunk Size: You can also estimate the size of a shrub or tree root ball based on the size of the trunk. According to the Generic Rootball Size Guide from the Tennessee Arboretum, multiply the diameter of a trunk by 18 for trunks between ½”-1″ in diameter, and 16 for trunks between 1″-1½” in diameter.