planting swamp cedars in the driveway


Hi, I have a shared driveway with a neighbour, and wanted to cut a two foot trench through the driveway on the property line, and plant a swamp cedar hedge. So asphalt on both sides. Will they survive? Thank you


Thank you for contacting the Toronto Master Gardeners.

Without knowing your site conditions; full sun? shade? part sun? clay, sandy or loamy soil? water availability?  it is difficult for me to say whether eastern white cedar (Thuja occidentalis) also commonly called swamp cedar will survive.

This evergreen is commonly found throughout Northwestern Ontario, and is most often found on moist, nutrient rich sites, or other drainage- ways.  As mentioned this tree prefers moist soil, it will tolerate some shade but prefers full sun (6 hours) and will grow in a variety of soil however, it does not tolerate spray from road salt, which might be an issue when planted down a driveway.

There is a wealth of information on our website on planting a cedar hedge. Simply type Cedar Hedging in the Find It Here box located on the right side of the page.

The following information is from a few of our archived posts:

Eastern White Cedar, or Thuja occidentals, is a popular choice in Toronto because it is a native (so attracts local bird species looking for food and cover), it is the least expensive to purchase and usually comes with a small root ball, which makes them lightweight, so easy to carry and plant. The can be pruned to a width of two feet and can be planted so that the root ball sits close to the fence. This means you can plant in a bed as little as two feet wide, if your space is limited. They look great if they are hedge trimmed annually on both sides (otherwise the side against the fence will hang over into your neighbours) and along the top at your preferred height.

The native white cedar (Thuja occidentalis) is particularly prone to thinning in the lower branches when planted close together. The crowding reduces the sunlight reaching the lower branches, and often lose their foliage. If you’ve ever hiked through a cedar forest, the lower dead branches fool you into thinking an easy hike. However, the pointy dead branches that seem to interlace with one another quickly informs you that it’s not as easy as that!

Pruning is essential to keep cedar hedges thick and healthy from top to bottom, otherwise, thinning foliage and dying branches from the bottom will happen within a few years of planting. Water also is essential, as cedar are naturally in moist conditions. Fertilization will help with new growth.

Within a year or so of planting, light pruning should be done when the new growth is visible either each spring, or at the very least, every other spring. It helps the new growth stay closer to the trunk, rather than reaching out to find the sun.

Deep watering also is essential. This means a soaking each week – to about 2.5 cm when you stick your finger in the soil to see that it is wet. Some people use trickle hoses to soak the base of the tree, rather than sprinklers, which gets everything wet. To maintain moisture longer, a good mulching around the base of the hedge will help. To a depth of about 10 cm, be sure the mulch does not touch the trunks. That can encourage disease.

Fertilizing is best done between the end of April and the end of June.  This is the ideal period where the hedge will grow the most.  Most evergreen tree and shrub fertilizers are high in nitrogen that encourages growth of foliage.  The most common fertilizer for your cedar hedge is (18-4-8) and can be purchased at most garden centres or big box home improvement stores. On the growing branches, some lateral growth in the coming spring, may fill in the gaps you can see from your side of the hedge.”

You may also be interested in our Gardeing Guide on Evergreens Suitable for Hedging

No matter what tree you choose in the end, it is vital that it is planted properly.  Even a healthy tree ideally suited to your location, receiving all the TLC you can give it, will suffer and even die if it is incorrectly planted and not cared for post-planting. For more information, please go to Planting a Tree: A Toronto Master Gardeners Guide

You may also find our Gardening Guide on mulch useful:

If you do not have time to water, consider adding a drip irrigation or soaker system.  This can be either on top of your soil (covered with mulch if you do not like the look of bare hoses), or buried in the soil at planting time (especially if you will not later be digging into the soil and thus there is no potential for accidental damage to the system post-planting).  These are easily purchased at many gardening supply, hardware or box stores, and you can install one yourself or have it installed for you.