Thursday, December 19, 2013

New Resource: Botanical Garden List

You never know who you'll see at a botanical garden!
Here a cute frog crashes the party at Powell Gardens' Festival of Butterflies.
Photo by Greg Boege

Dear Garden of Aaron readers,

Thanks for all your support and valuable feedback over the past year!

I would like to draw your attention to a new resource - a list of U.S. botanical gardens that I have added to the right sidebar. 

I'm sure this list is not comprehensive, but I hope that I've included most of the biggest and best botanic gardens in the country.

If I've missed any notable names, please contact me or use the comments section below to let me know.

(In the future, I hope to add a list of major U.S. arboretums. Since some botanic gardens - like the one in Dallas - seem to define themselves primarily or equally as arboretums, they'll end up on that other list.)

Hopefully these links to botanic gardens around the country will help you to discover gardens in your region or give you ideas of gardens you can visit when you travel.

What are your favorite U.S. botanical gardens? I've got to give some hometown love to Cheekwood, but I also was incredibly impressed with a visit a couple of years ago to Powell Gardens outside Kansas City, particularly the 12-acre Heartland Harvest Garden. Well-played, Powell!

Which garden would you most like to visit? I have to say that I'm hoping to visit some of the famous nearby gardens in upcoming years, including the botanical gardens in Memphis, Atlanta and St. Louis, plus the University of Tennessee Gardens in Knoxville!

Thursday, December 12, 2013

Eight Top Performers from 2013: Creeping Raspberry, Aucuba, Camellias and More!

Apologies for the recent silence.

I was traveling for a while and then sank into a curmudgeonly funk due to November's extraordinarily cold weather.

Having shaken off that funk, this feels like a good time to look back on some of the lessons learned from 2013. I'll start by looking at the best performers - either new discoveries or proven favorites.

Creeping Raspberry

Rubus calycinoides, Creeping Raspberry - Winner, especially in sunny situations. As you can see from the photo above, Creeping Raspberry blankets the ground, preventing weeds, but so far it has not displayed any tendency to spread out of control. (Everything I've read about this plant is that it spreads through above-ground runners, not below-ground roots, so it seems unlikely that the plant would travel underground and pop up feet away, as can happen with other sneaky groundcovers like Blue Star Creeper.) Note that this photo, like the others below, was taken a few weeks ago. Since then, cold temperatures have added much more reddish tones to the plant's leaves. I'm looking forward to seeing the changeover from old to new leaves in the spring and also to seeing what this plant is capable of doing in 2014. Indeed, I'm happy enough with this plant that I plan to add several more specimens in the spring. After that, I imagine I'll be able to separate rooted runners and propagate it within the garden and should not need to buy any more for the foreseeable future. I'm also keeping my fingers crossed for flowers and berries next year, but maybe my hopes are too high in that department.

UPDATE 4/2017 - I ended up removing creeping raspberry from the garden in 2015. See this post to read why it got the heave-ho. (I should say that even though it was a royal pain to dig up and remove creeping raspberry, at least removal was just a one-time job. It didn't try to return from any rootlets like Ajuga, hardy blue plumbago and bloody geranium tend to do.)

Ajuga genevensis

Ajuga reptans "Burgundy Glow"

Ajuga - Winner (mostly), Ajuga is an unpredictable plant. In one place, it seems to have petered out. Perhaps it got too much shade? But most of the others I've scattered around the garden are thriving, especially in partial sun settings, with one doing well even in full sun. My favorite may be Ajuga genevensis, it's not variegated or flashy, but it does produce a dense, low carpet of pleasant green leaves. Ajuga genevensis also seems to hold up to cold temperatures better Ajuga reptans. So why is the genevensis variety so much harder to find in nurseries and catalogs??

The purplish ajugas like Burgundy Glow are beautiful, but they do seem to have a tendency to revert to a darker-leaved plant, so you may have to keep a sharp eye out for those reverts and remove or transplant them if you want to keep a patch consistently purple. I like that ajuga is evergreen in zone 6-7, although it does get tattered over winter. I like the springtime flowers. I like that it seems relatively tough and spreads at a moderate, but not ridiculous pace. I like that it seems relatively easy to uproot and keep in bounds if necessary. My goal in the future is to have mostly plants as groundcover and not much mulch. I see groundcovers like ajuga and creeping raspberry being a big part of that plan. In 2014, I'm eager to try the Chocolate Chip variety, which I hear is an outstanding ajuga.

UPDATE 4/2017 - Way too aggressive in my garden. It wants to create a monoculture (at least at ground level), it's unattractive for a good bit of the year and seems to offer very few ecosystem benefits. In my garden, Ajuga reptans does suffer random dieback sometimes, but the other species (A. genevensis and A. tenorii) seemed to thrive and spread, usually by rhizome, but occasionally also by seed. I wish I could say that I'd evicted this from the garden, but it's an ongoing effort and in some places - especially where it has insinuated itself among the roots of shrubs or other perennials - I'm not sure what to do. I can't really dig deeply in those places to remove the roots completely and spraying seems to run the risk of damaging the other plants, so I'll probably just keep pulling and pulling until the Ajuga (hopefully) gives up the ghost.

Aucuba japonica, Gold Dust Plant - Winner, planted in autumn 2012, so far my Aucuba shrub has thrived. The variegated leaves really light up a dark corner. I hope to add more Aucuba to the landscape - particularly as having multiple male and female plants would give me the hope of getting large ornamental red berries. Warning -- those berries are apparently inedible and slightly poisonous for humans, but hopefully birds would enjoy them. Note that the leaves in this photo are a bit droopy. That's just because I took the photo on a cold day. When temperatures are below freezing, Aucuba droops. Think of it as your own biological thermometer. As temps warm, the leaves perk back up. Loving this plant so far.

UPDATE 4/2017 - Still loving Aucuba. I should say that while it has done well in partial shade in my front foundation, it struggled when I tried a green-leafed variety in a more sunny, exposed setting. It also got chomped to pieces by deer when placed out in the landscape. But it's been a fantastic evergreen through heat, drought, cold, snow, ice, etc. in my east-facing foundation bed. I should really post an update photo to show what it looks like now.

Sorry I don't have a beautiful Camellia flower to show you. Many of the early-blooming ones have finished or got zapped by freezes. This Camellia japonica has not started flowering yet, but it has many fat buds that hold the promise of a beautiful show in the spring!

Camellias - Winners, with reservations. All the camellias in my garden so far have done fairly well with minimal supplemental water and just a bit of acidic fertilizer. This November, I swapped out a mildew-stricken crape myrtle and added yet another camellia - Winter's Joy. Supposedly hardy to zone 6 and with an upright, narrow growth pattern (10-12 feet high by 4-feet wide), I hope this camellia will perform as well as the others have.

But that's not to say everything is perfect with the camellias. (Has there ever been perfection in a garden since the time of Adam and Eve?)

One of the camellias I added last year dropped a lot of buds this winter in our November cold snap (lows in the teens) and barely flowered at all.  Apparently, camellias (some more than others) are susceptible to this sort of bud drop when temperatures fluctuate wildly, as they have done so far in Middle Tennessee this winter, from a low of 12 degrees Fahrenheit in November to a high of 76 degrees Fahrenheit last week.

And then there's the whole issue of zone pushing. Many camellias are only listed as being hardy to zone 8 or the warmer parts of zone 7. But there are more and more camellias - such as those in the Ice Angels(R) series - that are advertised as being hardy down to zone 6, which technically should mean that they are able to survive temperatures as low as -10 Fahrenheit. Fortunately, I have not encountered anything like those temps since I started gardening Middle TN. We're officially listed as being on the colder side of zone 7 these days (0-5 Fahrenheit maximum low temperature in an average winter), so there should be plenty of camellias that survive here.

But I have to recognize that I'm pushing zones here a bit. I'm thinking that I should look for camellias that flower either early or late - or ones that are known for having especially hardy flowerbuds. After all, I'd like to have camellias not just for their evergreen leaves (which are attractive on their own), but also for their flowers. But many of those flowers and flowerbuds will be killed by sub-freezing temperatures - certainly by temperatures in the teens or low 20s, so then I just have the sad spectacle of fallen buds or melted flowers on the stem. (As this source says, "Most blooms freeze, brown and turn to mush at about 32F.") I guess this is why I don't see many other camellias planted in my neighborhood or other Nashville area gardens. I imagine that Camellias are probably best suited for climates reliably warmer than Middle Tennessee - such as parts of the Deep South where it doesn't get to be 12 degrees in November!

That said, I still like the camellias a whole lot. If I pick the right varieties, I should be able to have a nice flower show in late autumn (October to November) and spring (March and April) even in harsh winters. And in mild winters, like the ones we had the last two years, I might even get to see flowers all winter long.

UPDATE 4/2017 - I still love the two camellias that were already planted right next to the porch steps when we bought the house. I mean, they're clearly too close to the foundation, but maybe that's why they have survived and done pretty well over the years while other camellias that I bought and tried to use in more exposed locations got blasted by cold winter winds? I like that we have both a Camellia sasanqua (blooms in late autumn, attracts honeybees) and C. japonica (does not seem as attractive to pollinators, but it does bloom for months in late winter to spring. In fact, it's just finishing up now in late April and I can see on my Instagram feed that it started blooming in February, so that's at least 8 weeks of blooms!!)

Dixie Wood Fern

Dryopteris x australis, Dixie wood fern - Winner, the books call this native fast-growing and drought-tolerant. The books would be correct (so far). This is my only fern and I'm loving it. I'd like to add more ferns, but I don't have many of the shady spots that ferns like. I planted Dixie in the spring, so this is my first winter with the plant, but since it's hardy to zone 5, I presume it will overwinter here just fine (although sadly, I don't believe it's evergreen). It's worth noting that the fronds which fell over were presumably felled by a cold snap. I imagine those fronds are dead and will eventually decay, but for now they are still green and adding a beautiful ferny presence to the garden even splayed on the ground.

UPDATE 4/2017 - Still a nice, solid performer, although the persistent old fronds are pretty messy. I guess they do decay, but slooooooowly. Honestly, I'm not that big into ferns in the garden at the moment, but I still have a few, and this is probably my least favorite at the moment. Ouch. Sorry about that, Dixie wood fern.

Coneflower seedheads
Echinacea purpurea, Purple Coneflowers - Still Winners. The coneflowers bloomed all summer and into autumn, with the clumps getting larger and more beautiful as they mature. Since I leave the seedheads for the birds, I'm starting to see more and more self-sown seedlings pop up here and there, so hopefully I'll have many more coneflowers next year. I love them for their natural beauty, plus of course for the way they attract bees and birds. This year, I also tried a trick I read on the Internet -- I cut off entire mature seedheads and buried them in various places throughout the garden beds - including in some partial shade spots. (So far, all my coneflowers are growing in very sunny settings - I'm curious to see how they'd do in a morning sun / afternoon shade situation). I'll post an update next spring as to whether this was a successful propagation technique.

UPDATE 4/2017 - Purple coneflowers perform fine in the garden. The straight species ones are dependable and come back year after year. The flowers are pretty and attract pollinators (especially bumblebees), while birds do eat the seeds from the seedheads. That said, purple coneflowers can look pretty awful in a drought, especially when growing in full sun. They seem most robust and floriferous when growing with morning sun and afternoon shade. They can seed around quite a bit (especially if you leave the seedheads standing over the winter for the the birds), but seedlings (or even established plants) are easy to pull and remove if you find yourself with too much E. purpurea.

Gaura lindheimeri 'Siskiyou Pink'

Gaura lindheimeri - Still Winners. Love, love, love the gauras. Since it didn't get too hot this year, they bloomed pretty much from late spring all the way through to autumn. The big, billowy plants attracted lots of bees, ladybugs and other beneficial insects like green lacewings, who came to feast on the many aphids this plant attracted. (If you're grossed out by aphids in the garden, Gaura might not be the best plant for you. I cut a couple sprays of flowers to take inside before I realized the stems and especially stem tips were covered in aphids camouflaged as flower buds. Yech.) I didn't treat the gauras with any insecticide or even try to wash off the aphids with water, I just let the predator bugs do their thing and they soon had the problem under control, but I think there always a few aphids on the plants throughout the summer, which actually probably was a good thing as it kept up the predator insect population enough to protect the other garden plants.

In early winter, the stems turn red and then tan. As I recall from last year, they may be a bit of a frizzled mess by spring, but for now, they still have some nice billowy presence to them - and a bit of green at the base. At a time when many other perennials have died back and annuals have plain died, it's nice to have the gaura's presence in the garden. I hope to add more, particularly full-size ones like Siskiyou Pink. Gaura has been very tough and drought-tolerant for me, plus it's survived several typically wet winters despite my heavy clay soil. Other gardeners have not been as lucky with overwintering gaura outside of its native SW climate, but I'm keeping my fingers crossed that these gaura will survive for many more years. And meanwhile, a couple of the gauras have self-sowed to give me a few new seedlings, so I do have a few young next-generation plants in the garden in case the parents shuffle off this mortal coil.

UPDATE 4/2017 - My gauras proved to be short-lived perennials (typically 2-3 years?). I suspect they were killed by a combination of cold temperatures and heavy, wet clay soil. Still, I missed the pretty flowers and long bloom season and just bought a quart-size plant this year. I've tried installing it on a slope where hopefully the drainage will be a little better. We'll see if that helps.

Geranium x cantabrigiense "Biokovo"

Geranium, Cranesbills - All Winners. The Rozanne hybrids sprawled and bloomed from summer through November, while x cantabrigiense 'Biokovo' and sanguineum 'New Hampshire' were much more compact with shorter bloom periods, but beautiful foliage and generally trouble-free plants in morning sun, afternoon shade settings. I know that Rozanne will be completely herbaceous, but I'm curious to see the extent to which the others die back. So far, Biokovo is looking mostly green and beautiful as we head into mid-December! Even if all the geraniums are fully herbaceous, I still think they are wonderful perennials from spring to late autumn in zones 6-7, and I hope to add a couple more Geranium x cantabrigienses in 2014.

UPDATE 4/2017 - I did add more 'Biokovo' geraniums. They're fantastic. Truly one of my favorite, most dependable plants. I think they'd be happier in a cooler and/or shadier setting (most of them get full sun all morning and into early afternoon in the east-facing front foundation). They get a bit wilted, but hang tough through the summer. And they really shine in autumn, winter and spring. They're true evergreens, with some red leaves for bonus color. They form a relatively thick groundcover that excludes weeds, but they spread at a measured pace and are easy to remove if they stray beyond their boundaries. 'Rozanne' is also a nice plant - loooong blooming season. It's probably an amazing garden plant further north. Here, it wilts awfully bad during the summer and seems to be a little short-lived. Maybe 3-4 years? Plus it involves a little more work - benefiting from being trimmed back once or twice a year, and all the dead stems need to be pulled out in late winter (since it dies back to the ground and then comes back from the roots - or not). I do wish to retract my recommendation on G. sanguineum. This plant has turned into a bit of a nightmare. I thought it was spreading too aggressively and overwhelming other nearby plants, so I decided to rip it out. Ha. Geranium sanguineum - or bloody cranesbill - has deep, thick, red roots. They hang on touch and snap easily (at least in heavy clay soil). And the plant regrows from even small root fragments. The upshot - I've dug up certain areas oh, half-a-dozen times trying to get rid of G. sanguineum and probably will be digging all this year trying to eradicate the last remnants. Meanwhile, I've got quite a few holes and blank spaces in my garden where I can't plant anything lest I need to excavate again in a search for G. sanguineum root pieces. Ugh. Don't plant it. (Unless you're in its native range - Europe, far western parts of Asia. In that case, I guess you could plant it if you wanted a really tough, aggressive native romping through your garden.)

Stay tuned throughout the winter for more reflections on how plants performed in 2013. Here's a hint - they weren't all winners! ;-)