Wareham Garden Club's September Tips for Horticulture by Joyce Holster, Horticulture Chair
PLANTING FOR DIFFICULT PLACES
There are many difficult planting conditions we face when gardening. In general, plants will grow best in their favorite conditions. Amounts of light, soil quality, and water in your planting area define which plants will work. Planting on a slope can be hard because in heavy rains runoff can be very strong. Water flows rapidly down, not soaking into the ground. Often, slopes have only shallow levels of soil.
A slope is the amount of rise or fall of the land over a distance. Rise divided by length times 100 is the percent of slope.
The slope in this photo is more than we would want in a garden. Water and erosion issues need to be considered when planting on a slope. Plant roots hold the soil in place, and foliage covers the soils and reduces the impact of rain. A variety of plants works best rather than a mass planting of one thing. First choose plants for the amount of light you have.
Plants get less water on a slope. Eliminate plants that need a lot of water. You are using the tough plant roots to help lessen erosion. Cut the bottom of a plant pot off and push it down around the plant into the dirt a few inches. Choose a pot that is at least as wide as the plant drip line. This will hold some water at the plant feeding area to drain into the roots.
The best plants to choose for a slope can live without deep, rich soil (erosion). For ease of maintenance, plants on a slope should not need extra watering or much weeding after they are established. You can also cut out slightly to make a terrace effect which makes the actual planting area more flat. This allows for some soil amending. Keep in mind that cold air sinks and water seeks the lowest level. Avoid planting in straight rows, which more easily erode from heavy rains.
Start with the area in small segments that can be cleared and planted at the same time (if you clear a large area and do not plant it, a heavy rain can wash out a lot of soil). If using an herbicide, leave the dead roots in place until ready to plant. They will hold the soil in place.
South and west facing slopes are hot and dry out quicker. For any of you who travel regularly along the Canal Road in Bourne you may have noticed the fine job that the Army Corps of Engineers has done choosing plants for that slope. The hill is planted with lupine, black-eyed Susans, daisies, kerria, and Russian sage. In January our program will be presented by a Cape Cod Canal Ranger with a film on the hillside plantings.
Aggressive spreaders have the tenacity for flourishing on a slope (please stick to vigorous growers, not invasive plants). Other plants which can be successful can be obtained on line from www.wmassmastergardeners.org Western Mass Master Gardeners. Note the additional plant info, i.e. berberis, notes it should not be planted because it is invasive.