Growing Red Alder in the Pacific Northwest Stream Side Garden

The Red Alder (Alnus Rubra) is a tree with a dodgy reputation. In forestry circles, it has become known as a weed tree. Alder trees will spring up anywhere the soil has been disturbed. Yet this very attribute makes it a valuable plant for the streamside gardener.

Red Alder Trees Thrive on Stream Banks and Disturbed Areas

Undertaking a renovation in the garden, or gardening in an area that experiences frequent flooding? If so, the red alder tree is the perfect candidate. Red alder loves the light, and it grows well in open areas with disturbed soils. Red alder enriches the soil where it lives. Nitrogen-fixing bacteria on its roots take nitrogen from the air and put it into the soil. Planting a red alder tree is like planting fertilizer.

Alnus Rubra Trees Provide Vital Nutrients for Stream Side Gardens

On a large property with a wild sort of garden, let red alder run wild too. In the fall, this deciduous tree will drop ample quantities of leaves throughout the stream side garden. These leaves fall in the stream, providing homes and food for invertebrates. Fish eat the bugs, and the red alder supports this important food chain.

On land, deciduous leaves from the red alder tree support an entire ecosystem of land invertebrates like beetles, centipedes, spiders and worms. Some of these animals create garden soil, while others are beneficial garden predators. A healthy invertebrate population also supports garden birds as well.

Red Alders Require Little Care in the Pacific Northwest Native Plant Garden

The red alder is an ideal tree for the Pacific Northwest native plant garden. It is found within several hundred kilometers of the coastline where the rain is plentiful. Plant red alder trees on well-drained soil where they can fix nitrogen and increase soil fertility. Plant them in bright light conditions to emulate the disturbed conditions that they would naturally find near the stream side. Alders will naturally reproduce in the garden, and soon there will be plenty to give to neighbors as well. The alder tree will reach up to thirty-five meters in height, so give it room to grow.

Grow Red Alders With Native Shrubs Like Salmonberry and Thimbleberry

Try to emulate stream side conditions when growing red alder. In the stream side environments of the Pacific Northwest, salmonberry bushes (Rubus spectabilis) and thimbleberry bushes (Rubus parviflorus) thrive in the dappled sunshine under the red alder trees. Plants like sword fern and false lily of the valley can cover the forest floor under the alder trees.

Red alder is an easy tree to grow, and it is also excellent for the soil. Grow it as a fertilizer, as an important part of the ecosystem, or simply as a shade tree. Give it enough space and sunshine and it will grow vigorously in the natural or stream side garden.