Native Plants: Good for your Yard, Good for the Forests
3 things you can do
1. Reduce Invasive Seed Rain
The most important step you can take is to cut “survival rings” around ivy-infested trees. Ivy goes to seed when it climbs vertically, so severing vines saves the tree and slow ivy’s rate of spread. Do this for wild clematis vines (Clematis vitalba), too. Don’t pull vines down; it could damage the tree and endanger you - let ivy and clematis “wither on the vine.” .
Girdle English holly, hawthorn, and laurel (saw a ¼ inch “kerf” around the stem at breast-height), or cut and peel off a section of bark in spring when the bark is "slipping." Invasive trees will resprout, so break off new shoots to eventually starve the plant – this may take years. If you want faster results and have weighed the risks and benefits of herbicide applications, you may find licensed professionals on the Herbicide Info page. The Step by Step guide offers a detailed understanding of restoration practices so you can do-it-yourself or direct hired help. If you're in a wetland or slide-prone area, check Environmentally Critical Area status with your local jurisdiction before clearing invasive vegetation.
Other invasive seed rain sources in Western Washington include: English and Portuguese laurels, pyracantha, cotoneaster, sweet cherry, wild plums, European mountain ash, Japanese honeysuckle, and Bohemian knotweed (see SeedRain Species page).
Knotweed is an invasive plant that spreads primarily by root/plant fragments and yard waste dumpings. Cutting it back will cause 20 times the root suckers, much like horsetail (native) or holly (invasive). Knotweed roots can grow 15 feet deep along streambanks, making removal impossible without causing erosion that can smother salmon eggs. The autumn leaf drop of knotweed has almost no nutrition, so neglecting infestations will severely degrade a diverse food chain that feeds salmon fingerlings.
Eradication of knotweed requires infestations to be unpruned for licensed professionals to apply wetland-safe aquatic herbicide approved by the Dept. of Ecology.
2. Increase Native Seed Sources
Native plants provide a diversity of food for native pollinators and birds in extended seasons.
Plants with high habitat value that can spread naturally include:
Inexpensive bareroot native plants can be ordered every January through most County Conservation Districts.
3. Enhance the forest's soil “sponge” to
preserve water quality
Any loss of tree cover or soil health will exacerbate flooding and stormwater pollution. "Stormwater" is rain run-off from roads, driveways, lawns, and combined stormwater-sewer overflows. Stormwater is considered the #1 source of toxins fouling Puget Sound and other water bodies.
Evergreen trees intercept twice the stormwater than deciduous trees during winter rains. Plant native evergreen conifers (Douglas fir, Western Red Cedar, Western Hemlock, Sitka Spruce, Grand fir) on appropriate sized properties to accommodate their mature heights (avoid overhead and underground utilities). Smaller properties might be better with shorter trees, such as Shore pine or Pacific Yew, or evergreen shrubs and groundcovers (see Step by Step Guide for more plant suggestions).
Another way to recreate the forest sponge is to transform your lawn with a diversity of plants - native plants are better, 4-5 times more attractive to native birds and pollinators. Improve your soil's sponge by leaving appropriate organic matter ("grass-cycling," leaves, and plant trimmings) spread out, including messy areas for ground-nesting pollinators, leaving any stumps intact as wildlife snags with rotting roots in the ground. Nurselogs (with ground contact) and any "habitat piles" of kindling-like branches should be kept away from fire-safe zones around structures. Ask local tree services for arborist’s woodchips to mulch trees (keep woodchips 4 inches away from plant stems) and perennial beds. Create a 1-ft deep berm of woodchips to filter runoff from driveways and dog runs. If you're not in a slide-prone zone, consider a raingarden to capture and absorb rainfall from your roof. An excellent summary of “green infrastructure” to reduce stormwater runoff can be found at Tox-Ick.org.