Toughest of the Tough Part II: Perennials, Grasses and Deciduous Shrubs

Time for Part II of Toughest of the Tough, a look at plants that have proven a high level of resiliency. Last week we looked at evergreen plants, this week it's perennials, grasses and deciduous shrubs. From extreme heat and drought to record rain and record late snow, these worthy plants have not complained, still look great, and are low maintenance. Let's jump right in.

For late summer color you cannot beat asters (I know, they are now in the genus Symphyotrichum). One of our natives, Symphyotrichum subspicatum or Douglas' aster is so prolific, it's almost a problem. It's difficult to kill. Yet despite their tendency to spread by seed I keep them around for the pollinators. Plus, they are just about the first aster to bloom. Pictured is a mix of who knows what, I have so many and there's been a lot of hanky panky out there, but the ones in front are definitely Douglas' aster.

Late in the spring to emerge but totally worth it is Amsonia hubrichtii, Arkansas blue star. This soft fluffy perennial is very sculptural. These are now established and take little supplemental summer water. Nicely, they have not baked in the sun or dried out at all. 

The super added bonus is this: The best autumn color of any perennial I know. Still soft and fluffy to the end, this easy care perennial is a total winner in my garden.

Here are a few in a row in mid-November. They are in mostly sun and average soil. 

Phlomis russelliana is a semi-evergreen perennial that keeps its basal foliage year round. It blooms with yellow flowers in spring, the leaves on the flower stems eventually fall away leaving a dark brown stem with pom pom seed heads that persist through winter until I actually cut them off in spring. It seeds around a little in my gravelly garden. In fact, this one pictured is a volunteer. Easy, pretty, very little if any summer irrigation.

Baptisias or false indigo have a substantial tap root. I am assuming that's why they look good no matter what all summer long. I never water them and they are always upright and pretty, even long after the flowers have faded. This is simply Baptisia australis, native to the eastern U.S. Bees like it, too.

Its seed pods are quite attractive.

Both Baptisia australis and a yellow form (unknown variety) in the labyrinth garden. 

Both the Eriophyllum lanatum or Oregon sunshine and Eschscholzia californica or California poppies in this photo are worthy of mention. The poppies migrate around from year to year and are a good source of pollen for insects. They are basically perennials unless a harsh winter kills them. The Eriophyllum lanatum likes it hot and dry, plus the winter wet doesn't seem to bother it much. Both are great for full sun and poor soil and are native to Oregon.

Marrubium incanum, also known as horehound, is a tough Mediterranean native that also likes it hot and dry. They laugh at the sun and heat and dry summers, looking silvery and pretty. They do get leggy at the end of summer and sometimes if I feel like it I cut them back but it's not necessary. Small, sweet and tough silvery plant for the sunny dry border.

Solidago rugosa 'Fireworks' is a stellar plant for late summer into autumn flowers that are a favorite of all kinds of bees. It is a handsome upright perennial at about 4' tall and I used to never water this. I did find that this summer its lower leaves were drying up especially quickly so I watered this patch twice. The upper parts of the plants were and are fine and are just beginning to flower now. It spreads by clumping and by seed, but I have room, so a large patch is dedicated to S. 'Fireworks' for the insects. In winter the dried seeds are a source of food for goldfinches, I have noticed. Easy, pretty for late season color.

Most roses have the reputation for being high maintenance, which may or may not be true (I don't grow many), but this Rosa glauca is no maintenance and is so forgiving. Its hips look incredible from summer right through winter. It has an upright then arching habit, quite elegant, and tucks into a mixed border with ease. The flowers are a pretty single pink, but truthfully I grow it for this, the hips. I rarely give it any summer water.

Nepeta or catmint is a well-used perennial throughout the gardening community and with good reason. It is reliable, pollinators are drawn to it and it does not ask for summer water. It does get leggy after its first round of flowers so a good haircut will give a fresh second flush of growth, although it is not necessary to do so. The cats like it, too. This is Nepeta 'Dropmoore'. Full sun and well-drained soil.

I used to think of Coreopsis 'Zagreb' as kind of boring, but wow this is an iron clad plant. It fills in between other perennials forming a kind of high ground cover, blooms for a long period of time and doesn't require supplemental summer water. When I can skip over a plant while watering, it makes me happy.

Stachys byzantina 'Helen Von Stein' is so pretty and fuzzy. What's not to like? It fills in where I magically want it to and it does not ask for summer water. At all. In fact, the drier the leaves the prettier they are. It is kind of a hot mess in January (being a semi-evergreen perennial) but it quickly grows out of its funky stage by early spring. The flower spikes you see here are about all it pumps out every year. I do allow these to flower (many people cut them off) for I have seen hummingbirds visiting them.

I know, I sound like a broken record but Geranium macrorrhizum or bigroot geranium is a winner. Part shade to part sun in my garden, it is evergreen and grows under trees! And spreads politely! Under thirsty maples and fir trees, too. Very little if any summer water, I have given them some extra this year as it has been exceptionally dry although I think they would live without. From snow to drought, this humble plant with spicy scented foliage is unbeatable. Geranium x cantabrigiense is also superb.


Saxifraga primuloides and so many other saxifrage species are evergreen, easy, pretty and add so much texture to shady areas. As long as they don't fry in too much sun or rot in heavy wet soil, they are very little maintenance and extreme weather does not seem to have an impact.

Sedum is the best, but truth be told they do appreciate a bit of water. These, however, Sedum oreganum, are in a very well drained site and do fine with no supplemental summer water. These extremely hot and dry summers we have been experiencing lately have seen some sedum shrivel up in my dry garden, but Sedum oreganum and a few other natives hold their own.

The same is true for Sedum spurium and its cultivars. It spreads, it blooms, it doesn't want anything. The lighter foliage forms tend to bleach out in hot summer sun, but the darker ones (such as this which is probably 'Bronze Carpet') do not mind hot sun.

Grasses: Left to right Stipa gigantea, Carex comans (ground level), Miscanthus s. 'Cabaret'

The full name is Miscanthus sinensis var. condensatus 'Cabaret'. It is a large upright warm weather grass with variegation. It comes on in late winter when we cut the old foliage back to about a foot or so then it quickly fills in to eventually reach 7' - 8' tall. It has not really flowered for us but its foliage is so lovely it doesn't matter. It stays pretty much reliably upright (in late autumn if we have relenting rains then it can open up a bit) and I have yet to water it this year. I did to get them established early on of course (with all plants, actually) but I'm surprised at how well they do without. 

West Coast native Muhlenbergia rigens, deer grass, is so sculptural this time of the year when its wands of shimmering flowers come on. It is evergreen at the base although I do cut them back in late winter to freshen them up. New growth quickly comes on, but the flowers do come on late in the season (now). Rarely gets any supplemental water and has had no issues with the bad winter weather, either.

Carex testacea, orange sedge gets a shout-out for being easy. I do comb through them once a year or so to get ratty old foliage out, but they have been reliable and a nice color accent for years. I receive a few seedlings here and there that I welcome. Reaches about 18" tall at maturity.

Not officially a grass but grass-like Ophiopogon planiscapus 'Nigrescens' and other species are super reliable and easy low accent plants for, in this case, shade. They are evergreen and spread slowly. I have never had any issues and they seem to live a long time. I have many throughout the shade garden and they require very little if anything from me and look smart year round. In sun they would burn up for me in these scorching summers but in shade they are fine.

Carex comans seeds around a lot in the gravel and just keeps on going. I comb them out with a rake about twice a year to freshen them up and, yes, a little water makes them look better. But I will say they have seeded around in the chicken yard, which was a barren wasteland before I dumped raked out debris up there (if you have chickens you'll understand), but these grow with no water and with no input from us there, so technically I'd say it's easy care. Up top are a couple Stipa gigantea that are tolerant of both weather extremes, but I do a good bit of maintenance in terms of cleaning them up after the flowers and stems are crispy. The basal foliage is evergreen but it too gets a good raking through every spring.

Deciduous Shrubs and Small Trees: This is Salix eleagnos var. angustifolia, rosemary willow. It is a small tree at about 10' tall and has narrow leaves that turn yellow in autumn. Absolutely lovely and is so light and airy it doesn't create a lot of shade (I have also limbed this one up to create a canopy). As a willow they normally would love moist soil but I have this in the center of the labyrinth garden which is very dry. It actually does well with just two or three soakings throughout the summer months. It bent down to the ground in the April snow event but sprang back up, just like a good willow would.

Cotinus or smoke bush is great for drought tolerance. It could not care less about snow or ice and during the summer months as it is a true champion of drought tolerance. Plus, its autumn coloration is spectacular. This is Cotinus 'Pink Champagne' from Xera Plants

Viburnum ellipticum, a native deciduous shrub to the Willamette Valley, was kind of a sleeper plant for me to be honest. But the thing is I never water these (I have several throughout the woodsy, shady and edge of shade areas), they always look perky and green and pretty and get better with age. I'm sorry, Viburnum ellipticum, for ignoring your fabulousness.

Here it is a little larger.

Another native shrub, Spiraea betulifolia is so under-appreciated and needs to be distributed more widely. It has wonderful autumn coloration, stays small-ish, requires little water and has pretty flowers in spring:

Just charming. The April snow caused a little bit of twig breakage but overall no problems. It bounced back, but it did bloom later than it had in past years. A fabulous small deciduous native shrub to tuck into a sunny (but not too hot and dry) to part shade area.

Another spiraea, Spiraea thunbergii 'Ogon' is so easy it's embarrassing. In more sun its yellow foliage is more pronounced. It has small white flowers in early spring and is really only without foliage for a couple of weeks in late winter from my observation. It is fluffy and pretty and its foliage color sets off more typical greens of the part shade/part sun area. I have this on the edge of a wooded area. I have never pruned it, really don't water it, don't fertilize (well, I don't do that at all, really), it just grows with no input from me and looks good.

Yet another spiraea! They are really all champions in my garden, I must say. I have many other species other than these three and they are overlooked but always look good. This is our native Spiraea douglasii. I have several in the back of the chicken yard and, boy, are they neglected. But they do this! So pretty, a good alternative to buddleia. They are not watered and aside from one along the hedgerow along our street that got sunburned, they all look fantastic. They do get large and spread, so not ideal for small gardens but what a wonderful native shrub if you have room.

Physocarpus capitatus, Pacific ninebark is yet another native deciduous shrub that can stand extremes on both ends. They can take sun but I have all of mine in at least part shade. I never water them (until this summer where they were watered probably three times just to keep the leaves from flagging) and they have a graceful arched branching form. They come back reliably despite what we put them through and I noticed last autumn a little color on the leaves. 

A sweet little annual native wildflower, Limnanthes douglasii, Douglas' meadowfoam, is a spreader but oh-so-charming and completely disappears by mid summer. This is one to attract those teeny pollinators difficult to see with the naked eye. There is always flying activity around these. Their foliage starts to come up in autumn and by spring they are blooming and keep on doing so for weeks. Super easy and a fun way to end this list of the toughest of the tough plants that say "whatever" to the intense weather extremes we have seen these past few years.

There are several other great plants out there that deserve mention, perhaps in another post another day. This selection was chosen for not only their tolerance of weather extremes but also for their low-maintenance and low-input from me. We'd love to hear what does well for you all, what your observations are in your own garden. Let's get the conversation rolling. We're all taking notes.

One more mention - I will be speaking for the Master Gardeners of Columbia County a week from today on Thursday, September 22, at 6:30 p.m. about groundcovers. Come if you can, it's free and open to the public. I'll have a couple of small plants for sale and rumor has it there will be tomato tasting. I'd love to see some friends there! The address is 505 North Columbia River Highway
St Helens, OR 97051.

That's a wrap for this week at Chickadee Gardens. As always thank you so much for reading and commenting, we love connecting with you all! Happy gardening one and all.

Comments

  1. Another great post. I grew the native Symphotrichum chilense but it pulled it out last year when it attempted a takeover. I'm missing it now but, as it's still attempting a comeback, maybe I'll see if I can keep it contained on a smaller scale. My attempts to grow both Baptisia and Amsonia failed, not lasting even a season, despite Sunset's claim I should be able to grow both - I may try at least the Baptisia again as it's supposed to like sandy soil. I inherited several Phlomis (fruticosa as opposed to russelliana) here but all, placed on the margins of my garden in areas that are especially dry, gradually died out over the last 10 years; however, I planted 2 this past spring in an area that offers more soil moisture as an experiment. I used a LOT of Geranium x cantabrigiense in my former shady garden but it died out quickly when I tried it in my current garden even in shade. I keep meaning to try Stipa gigantea. My go-to grasses here are Pennisetums (especially P. advena 'Rubrum') and various Seslarias.

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    1. Great feedback, Kris. Interesting what has died out for you over the years, it goes to show that every garden is completely different. Even from your former garden to this one. Thanks for sharing!

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  2. Anonymous8:15 AM PDT

    "Toughest of the Tough" part II is as informative as part I. I love how you mentioned winter interest in the form of seed heads. I appreciate a good winter garden, one that holds beauty through the quiet season (except for January, where even the toughest seed pods loose their charm...). I enjoy Amsonia hubrichtii's seed heads. I'm so in love with this plant for it's all year interest, I got a second one. With the promise of ornamental see heads I must find room in my garden for Phlomis russelliana and Baptisia.
    Love the grasses, hate the volunteers. After years of a complicated relationship, I settle on the orange sedge: gentler seedler and unbeatable color. I am also happy with aster, lamb ears, black mondo grass and saxifrage that you've mentioned.
    Finally, if I were ever to grow a rose it would be rosa glauca: sweet blooms, yes, but with the blueish foliage its amazing.
    Chavli

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    1. Thank you Chavli. Oh, I would love to have a fabulous winter garden - working on it! Seed heads are plentiful in my garden and the birds love them, too.

      Oooh, glad you got another Amsonia h. - such a great plant. Orange sedge is a favorite, I admit, a gentler seeder is an excellent description. Some of my grasses would be too much for a lot of gardens, quickly taking over. And Rosa glauca is indeed the best one in my humble opinion. That foliage! Swoon.

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  3. Even though my garden is in Canadian Zone 3B, and considered semi-desert so very dry, your perennial list and mine are so very similar. Great plants all. I would add some of the thistle group: Eryngium (seeds itself around a bit) and Echinops. I started seeds of Echinops tienschanicum and it is the best of the best. Tops over 6', defies wind and drought and has huge blue globes that the bees go wild over. Another favourite is Zauschneria (now Epilobium). So many others. Look forward to your next post.

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    1. Elaine, thank you for your comments and contributing to the conversation. That's so cool that our plants overlap even in your super cold 3b climate. Whoa! Super good to know. I agree wihth Eryingium and Echinops - absolutely - and their benefit to pollinators. And of course, Zauschneria - why didn't I include this one? I must have forgotten because it's fabulous. Cheers and great feedback.

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