Today, I shall embark on a two part series concerning a topic I am passionate about: spreading wood mulch. We as a nation are obsessed with covering every piece of flower bed real estate with some sort of mulch, usually ligneous in nature. There are many fine benefits to applying wood mulches; in this series, I would like to discuss the many steps we take in applying mulch at Wellfield. The first step we take is to put a fine edge on things. A good bed edge creates nice definition between spaces (flower bed and turf), is an important use of line in landscape design, and must be done prior to mulching to aide in mulch retention.
There are many edging options from which to choose, all with trade-offs. We use a “natural” edge along the miles of flower beds here at Wellfield. I made this decision early on for several reasons:
- Most adaptable: A bed edge is going to change rather rapidly in a young garden with trees and shrubs growing quickly. A natural edge can be easily and quickly expanded/changed with a few chops of the edging shovel.
- Soil retention: Wellfield Botanic Gardens has a very sandy/gravel soil. Soil and mulch would easily wash into the turf after a hard rain if it were not for the three to four inch trench created by hand or edging machine. Our natural edges act as a small swales and help retain all things flower bed. Most other installed edges would only have about two inches of material above grade to retain the mud slide descending en masse upon the hapless blades of grass, and that is not enough in most instances to stem the tide.
- Aesthetic: I must admit I am just partial to the definition created by a clean, deeply trenched edge.
The great downside is the labor and time required once a year to “redefine” the bed edge. Wellfield staff and volunteers travel many linear feet retrenching flower beds. The first step,of course, is to cut the edge and push the chopped material up into the bed for pickup. A crew then comes along removing the grass, leaving as much soil as possible. The remaining piled soil then is raked smooth up into the bed. The edge definition is then maintained using a string-trimmer, cutting vertically every few weeks through the remainder of the season.
Josh Steffen, Horticulture and Facilities Manager