I need to install a privacy hedge along a fairly busy pathway beside my property. The hedge will run from full sun to full shade, and I need to consider male dogs urinating on the hedge along the pathway. The hedge will be beside a two-tiered perennial rock garden, so I would like a green hedge. (As opposed to something variegated.) I am in Kingston so, to be safe, zone 5A.
We have helpful information on our website, see Evergreens Suitable for Hedging: A Toronto Master Gardeners Guide, which provides some suggestions as to appropriate hedges, along with hardiness and required growing conditions (sun/shade). Ornamental Shrubs for Various Light Conditions: A Toronto Master Gardeners Guide is also an excellent resource; note that certain can be used as hedges, and may suit your pathway.
As well, if you search our Ask a Master Gardener website using the word “hedge”, you will find a number of Q&A that provide helpful information. For example, Privacy Hedges is particularly instructive.
The issue of dog urine dotted along the hedge pathway is a concern because the urine has a high nitrogen content (so the result is similar to if you have over-fertilized the area). One strategy is to water plants within a few hours of the doggy visits, to dilute the urine effect, although this would take time. Perhaps a thorough watering on a regular basis would do the trick. Also, as dogs don’t like getting wet, installing a motion-activated sprinkler might be a good deterrent. Here’s a Q&A that discusses some strategies, Dog-friendly plants. Another consideration is to use good rich soil that contains organic matter (e.g., compost). This will support healthy microorganisms and can help buffer urine (making it less harmful to the plants). Remember too that sometimes dogs mark territory by leaving very small volumes of urine behind; these small releases are less likely to harm the hedges than cases where the dogs release significant amounts of urine near the hedges.
Some literature suggests using hedges that are thorny so as to deter dogs, but these could harm both animals and young children, so I suggest this is not a reasonable option. Common rue (Ruta graveolens) discourages dogs from coming near, and planting these in strategic spots near the hedges may make a difference. Rue tends to spread madly, its leaves are toxic if eaten (so watch out if young children might wander by and pluck the leaves – although the smell is off-putting) and the plant has its own distinctive smell – this may make it a less-than-ideal solution for you. (I happen to adore rue!) Finally, using mulch that includes lots of citrus peels, chunky materials like pine cones or thick wood chips may deter dogs from coming close to the hedges. Dogs apparently also dislike the scent of coleus (which we can’t even detect!).