Cedar Hedges & Adjacent Grass

(Question)

Hi there, over the last few years I have been unintentionally neglecting my cedar hedges. They have grown to be quite tall and I would like to trim their height, as well as give them a haircut all around so they look nice and clean. Additionally, I have a patch next to the cedars which is supposed to be grass, but I am having trouble keeping grass here.

Questions:
1) How should I handle the cedars in regards to trimming their height, and trimming them all around?
2) Should I do anything at the base of the cedars to keep them protected? The dirt is quite silty.
3) What do I do to the soil adjacent to the cedars in order to grow grass that comes back year after year?

I am in Kamloops, BC, where the summers are hot and dry.

Thanks!

 

(Answer)

Thank you for contacting Toronto Master Gardeners regarding pruning of your cedar hedge and care of your adjacent lawn. We receive a great number of questions about good maintenance of cedar hedges and to read the questions and answers in our archive, go to  http://www.torontomastergardeners.ca/ and in the Find It Here search box type in “cedar hedge” for a list of pertinent questions which you may find useful.

It is important to know that all new growth of cedars is produced in the green ends of branches which may be trimmed back but must retain some new green growth as this species does not generate new growth from old wood. Care will be needed to remove the ‘rusty’ areas of foliage to ensure that any green growth is preserved in order to regenerate. Totally brown limbs within the shrub may be safely removed. Use sharp shears disinfected with rubbing alcohol, wear safety protection such as glasses and work gloves, and possibly wear long sleeved tops and full length trousers to avoid nasty scratches. Spread a tarp under the area to be trimmed to make cleanup easier. To decrease height, remove no more than 20% of the tree’s height.

Cedars benefit from water, and from sunlight so shape the hedge wider at the bottom than at the top. Nitrogen promotes green foliage so any fertilizer you may wish to use should have a high first number (the N for nitrogen). A mulch of compost or composted manure kept about 3+ inches or 8 cm away from the trunks would help keep the ground moist and add nutrients as it breaks down.

The soil adjacent to the hedge is undoubtedly filled with a dense network of fine cedar roots in which little will grow, and which thirstily sucks up moisture and nutrients, and the hedge shades, creating an inhospitable environment in which to grow lush grass. We suggest that you consider an alternate groundcover plant, and the following article may provide a suitable suggestion.

We wish you great success with your hedge and lawn substitute.

Broadleaf Evergreen Groundcovers: A Toronto Master Gardeners Guide