How to Design and Construct a Northwest Dry River Garden

When I purchased my current home I was somewhat appalled to find a large pool of water collecting on the east corner. The good news is that our lot, like most in the area, is built on glacial moraine, a strange heavily rocky soil filled with river rocks that is stable. The water came from rain runoff from neighbors and the street, this spot being the low spot in the area and filled with clay soil that didn't permit adequate drainage. Drainage pipe dug in underneath when we leveled the yard and connecting to the downspouts of our house carried the pool away but the natural terrain of a stream was allowed to remain. Instead of being an annoyingly soggy and plant desolate area, the northwest dry river garden constructed here has become my favorite part of my garden.

In building a northwest dry river garden, a number of tasks are required; installation of drainage pipe is actually the only optional task.

Design Considerations for Constructing a Northwest Dry River Garden

Identify any low spots in your yard that require drainage or suggest that a river might flow through the garden.

Decide if any areas along the dry river garden banks suggest natural features such as bogs, swamps, shady patches, places where the river would clog, and places where water would collect.

Determine which shade-loving plants and shrubs would offer the best, natural looking elements in the garden and would coordinate well with the rest of your garden design.

Determine how to provide the garden structure your northwest dry river garden needs including river rocks, gravel, bridges, and décor.

Northwest Dry River Garden Construction Step One

Remove all existing grass. Let chopped out hunks dry, then shake loose dirt from the roots before recycling.

[ See Photograph 1 : Riverbed after the grass dug out and lined with edge stones in the Northwest Dry River Garden ]

Northwest Dry River Garden Construction Step Two

Manage your river rocks if you have them. Collect all the river rocks dug up with the grass and collect them in a pile. Rinse the river rocks well before using in the garden. Use larger rocks to establish the edges of the river. Buy additional river rocks as needed.

Northwest Dry River Garden Construction Step Three

Place ground cloth along the streambed to help keep out weeds. Place the edges under the rock edging structures and tack down with hooks or pegs.

Northwest Dry River Garden Construction Step Four

Distribute purchased and saved gravel and river rock in a naturalistic fashion. Place larger river rocks randomly and fill with smaller stones. Save the prettiest colored river rocks for the top.

[ See Photograph 2 : River stones and prepared garden bed in the Northwest Dry River Garden ]

Northwest Dry River Garden Construction Step Five

On each side of the river, enrich the garden soil with compost, manure and peat moss. Spread out heavy deposits of clay into the better soils.

[ See Photograph 2 : River stones and prepared garden bed in the Northwest Dry River Garden ]

Northwest Dry River Garden Construction Step Six

Select plants that can endure wet clay soil that is shaded most the year. Plant choice considerations: ferns, hosta, rhododendron, bleeding heart.

[ See Photograph 3 : Hosta, Ferns and ground cover in the Northwst Dry River Garden ]

To create a mini-marsh: native shrubs select red or yellow twig dogwood, two types of pussy willow, and native grasses to give the impression of a swampy area.

To blend the river with existing lawn in a sunny area : Select sun-loving, blooming rounded shrubs to soften the square frame of lawn. Plants selections include native shrubs such as bearberry, privet honeysuckle, sumac to hang over the river, and a personal favorite of mine, skimmia. Also, on a drier bank I planted a native daylily. Around the shrubs plant ground cover such as creeping phlox and pachysandray have grown into a pleasing thatch.

[ See Photograph 4 : Daylilies and other sun loving plants in the Northwest Dry River Garden ]

To plant eddies along the dry river, use more sand and consider using iris, which looks like reeds. Use iris in several places along the edges.

Northwest Dry River Garden Construction Step Seven

If you can, build a bridge to cross the river and allow guests to visit other portions of your garden. Build other garden structures in as needed.

[ See photograph 5 : Sumac and River Bridge in the Northwest Dry River Garden ]

In designing your northwest dry river garden, look for areas where nature provided interest in a like manner and add garden structure. If you have low spots in the garden, don't eliminate them, instead I've found that working with such areas helps to enhance the pleasure your garden provides.