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CA Natives that Work in the PNW

created onMar 01, 2014 10:17 AM

categories California Native Garden and General Tips/Guidelines

I wanted to share some success stories of growing CA natives in rainy Western Oregon. I've only been doing this for a couple of years, and the plants I'm reporting have been in the ground for maybe 9-18 months. That said, it doesn’t take long to determine what’s going to work and what isn’t. Additionally, all of the reported plants have survived a year with rather un-California-like weather, including 7" of September rain, a week in December with back-to-back overnight lows in the single digits and a few more in the teens, 15" of snow, and a nasty ice storm. I figure that if they survived the past 6 months, they should do OK here.

Climate and soil info: I'm at the south end of the Willamette Valley, which has more of a continental climate than Portland and Seattle. Thus, our summers are a little warmer and our winters are a little colder. We supposedly average 46" of rain per year. Since I moved here (2006), I'd estimate that 38" has been more of the norm. The rainfall is also highly variable (50" in 2012 vs. 21" in 2013). Our dry season is roughly from sometime in June until mid-October. We're more reliably dry from July through mid-September. November and December are typically the wettest, and the precipitation begins to taper off beginning in January. We are overwhelmingly overcast from early November until about mid-March (not seeing the sun for a week or longer is normal… you'll need lots of coffee and tea to survive our winters). Winter fog (and freezing fog) is common in December and January. Summers are clear and dry, with highs and lows of about 83/52 F. We usually get 10-15 days of 90+ and occasionally hit triple digits (we had a three-day period of 105, 107, and 103 back in 2009… that’s right around the all-time high). Average winter highs/lows are about 45/35. We typically get about a month’s worth of overnight lows below freezing, but we're typically above freezing again by 10 am (this winter was the exception). Temperatures stay above 20 in most years, but can occasionally dip into the teens or single digits (Dec, 2009 and Dec, 2013). The all-time low is supposedly -12 F. My soil ranges from clay-loam in areas that have been mulched for years, to thicker clay (almost adobe) in untouched areas. My yard is also slightly sloped, which helps to ensure fair-to-good drainage in most spots. My soil pH is in the upper 5’s to 6 range.

OK, with all of the background information out of the way, here are some species that are endemic to CA that seem to be happy in my garden…

Arctostaphylos densiflora ‘Howard McMinn’ – Probably the most summer water-tolerant of the upright manzanitas and, thus, a really good pick for the PNW. Also grows relatively fast in full sun (from a one-gallon to 2' x 2.5' in 9 months). Mine took some foliage damage in December, but should recover.

Arctostaphylos ‘Emerald Carpet’ – Really nice hybrid ground cover that doesn’t need a lot of sun. Mine seems happy in part-shade. Will need protection if temperatures drop below the teens.

Arctostaphylos ‘Greensphere’ – Planted this one back in July. Dropped some leaves at first, but it’s since been very stable and made it through the winter with no foliage damage (hardy to at least -10 F). Known for its slow growth, but I've read that it will get to 2' x 2' up here in 5 years. Tolerates clay and our heavy winter rain. Nice mini-specimen to grow near a window.

Arctostaphylos hookeri – I'm growing both ‘Green on Black’ and ‘Wayside’. The former is in part-sun and the latter in part-shade. ‘Wayside’ isn’t super-happy in part-shade (some dieback) but is surviving. If grown in part-sun and given water 2-3 times a month, most of the A. hookeri cultivars should do well here. However, they will need some protection when temperatures get down into the teens.

Arctostaphylos ‘John Dourley’ – I've had this one in the ground for only 6 months, but I can tell that it’s going to do well in part-sun next to my (lightly-watered) lawn. A tiny bit of the foliage took damage in December, but it’s flowering now and looks great.

Due to our higher precipitation and longer growing seasons, CA manzanitas typically grow faster, a little larger, and sometimes have different forms up here. More info on growing manzanitas in the PNW:

http://xeraplants.com/Xeraplants.com/Manzanita_09.html

http://www.pacifichorticulture.org/articles/arctostaphylos-for-pacific-northwest-gardens/

Cercis occidentalis – Very nice small tree that tolerates clay. I planted a one-gallon a year ago in part-sun and it almost doubled in size. They supposedly grow quickly, so I expect to see that this spring. Young plants need to be protected from the cold when the temperature drops below 20.

Penstemon ‘Margarita BOP’ – One of the (relatively) few penstemons that can tolerate our combo of heavy rainfall and clay. I treated a couple of these like fuchsias and killed them. The one that I treated like a NorCal manzanita fared much better. Plant in full sun, with the crown at least ½" above the surrounding soil level and mulch with a 10" radius of gravel. Should be fully drought-tolerant here when established, but will tolerate very occasional garden water. Fully hardy here. When treated properly, this is a really nice plant. Hummingbirds are also big fans.

Rhamnus californica – I'm growing both the ‘Mound San Bruno’ and ‘Leather Leaf’ cultivars. Both survived the December freeze with light-to-moderate foliage damage and are currently pushing new growth. Full-to-part sun is probably best. ‘Leather Leaf’ is in part-shade and is probably growing a little more slowly because of that. ‘San Bruno’ can tolerate regular summer water and will grow nicely next to a lawn.

Ribes aureum gracillimum – One of my favorites. Very easy to grow in full sun and even seems to tolerate the compost that my wife puts around her nearby dahlias. Leaves stay on the shrub for most of the year, turning from light green to a wine-like blush in late summer. In most years, they hang onto the plant until new growth pushes them off. They also flower and produce berries at a young age. Fully hardy here and highly recommended.

Ribes sanguineum glutinosum – This is a really nice part-shade subspecies to compliment our native Ribes sanguineum. Looks similar, but the flowers are a lighter pink and the leaves are larger. Very tolerant of heavy winter rain, regular summer water, and our winter cold. Mine tripled in size in its first year.

Salvia spathacea – I'm growing both the straight species and the ‘Powerline Pink’ cultivar. The straight species does nicely in clay in part-sun. ‘Powerline’ will grow in the same conditions, but the flower stalk will grow too quickly and flop over. It'll look much better in the stress of full afternoon sun (with some occasional water). Both died back to the ground during our exceptionally bad winter, but will do well the vast majority of the time in our climate.

Zauschneria garrettii – Great fuchsia for hot afternoon sun and surprisingly tolerant of garden water (considering that it grows in the interior West). A really nice perennial to plant between your lawn and your more water-tolerant manzanitas. My hummers really like this one as well.

Zauschniera septentrionalis ‘Mattole River’ – This is one of the best West Coast native fuchsias to plant in a lightly-shaded border along a lawn. Very water-tolerant for a woody perennial. The gray-tined foliage also looks great.

Other CA natives that I've planted recently or will be planting soon: Arctostaphylos bakeri ‘Louis Edmunds’, Carpenteria californica, Ceanothus ‘Blue Jeans’, Ceanothus gloriosus, Ribes speciosum ‘Pincushion’, Ribes viburnifolium, Salvia sonomensis, and Thalictrum fendleri.

Ok, wow, that was a lot of writing. Hopefully somebody finds this information useful.

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