Thursday, April 27, 2017

Lots of Milkweed, Lots of Monarchs!

Very excited to see lots of monarch butterfly caterpillars - more than ever before - on the various milkweeds growing in the garden this year!

Monarch caterpillars on spider milkweed (Asclepias viridis)
Monarch cats on Asclepias viridis (spider milkweed)

Monarch butterfly caterpillar on rose milkweed (Asclepias incarnata)
Monarch cat on Asclepias incarnata (rose milkweed)

Monarch caterpillars on common milkweed (Asclepias syriaca)
Monarch cats on Asclepias syriaca (common milkweed... I didn't plant this one, it showed up last year, and this year has multiplied into three stems... I know it's got a somewhat aggressive reputation, but clearly it's a big hit with the monarch cats, and when it bloomed last year, I was bowled over by the incredible floral fragrance!)

All three of these milkweeds are native to Tennessee.

I hope to add two more to the garden eventually - A. purpurascens (purple milkweed) and A. tuberosa (butterflyweed).

What are your best butterfly host plants?


Follow Aaron Dalton on Feedio

Monday, April 24, 2017


Mind the gap!

Just a pic to illustrate the challenge of gardening on compacted Tennessee clay 'soil' (subsoil?)

It looks from this image like we hadn't had any rain in months.

But this is just what my soil looks like if we go a couple weeks with warm weather and not much rain.

(This pic was taken about a couple weeks ago. At the moment, much of the back yard looks like a shallow pond since we've had several days of hard rain with flood warnings across the area. But next time we have a couple weeks of dry weather, it will go right back to this cracked look.)

Could I amend the heck out of it? Sure, but it would be back-breaking, soul-crushing, expensive, time-consuming and ecologically-questionable.

Instead, I try to find ultra-tough plants - many of them natives - capable of surviving and even thriving in this pottery material.

Ultimately, where the plants thrive, I find that the soil does improve over time. Slowly. In a few hundred years of letting Nature work its magic, I might have some nice loam! 😉


Follow Aaron Dalton on Feedio

Friday, April 21, 2017

No One to Blame but Myself - Geranium sanguineum and Ajuga genevensis

Geranium sanguineum looks innocent, but it's a bloody nuisance to remove
Geranium sanguineum looks so innocent, but don't be fooled. I've tried ripping out this plant about five times and it keeps growing back!

I have weeds aplenty.

Some blow into my garden (dandelions, for instance), while others (looking at you, wild grape and oak seedlings) presumably are gifts from birds or squirrels.

That's OK. It's part of the gardening life. As I cover more ground with plants I do want in the garden, I anticipate gradually being able to displace some of those I don't want in the garden.

Meanwhile, I pull. And use the CobraHead.

But what really burns my biscuits are the plants that I add to the garden and then decide were awful, terrible, no-good mistakes that must be evicted.

Sometimes, I shovel-prune plants (looking at you, gardenia and Carolina allspice) because they have died. That's discouraging, but at least those mistakes don't come back to haunt me.

Other times, I have to work a bit harder to rip out overly aggressive / invasive plants (e.g., lemon balm, creeping raspberry, blue star creeper, sweet woodruff) that wear out their welcome, but at least those guys have the decency to leave for good when asked. (And when I say "asked," I mean ripped out of the ground.)

I had a tough time kicking out hardy blue plumbago. It kept trying to make a sly comeback with a stem or two here and there, but I think I've finally gotten rid of it.

Still, none of those compare to the challenge I've had removing Geranium sanguineum and Ajuga from my sticky clay soil.

This is a good time to note that there can be massive differences between the way different species from the same genus behave in the garden. What I'm trying to say is - Just because G. sanguineum has been a bully in my garden, don't tar all the other cranesbill geraniums with the same brush.

'Rozanne' hybrid geranium is a perfectly well-behaved herbaceous perennial that flowers for months. In my experience, it doesn't quite have the heat tolerance or drought tolerance to thrive in a tough-love garden setting in Tennessee, but it's still a very nice plant.

And 'Biokovo' cranesbill geranium (G. x cantabrigiense) is one of my favorite geraniums and one of the top groundcovers I've found for Tennessee. It's basically evergreen here, developing nice red tints to the foliage in winter, has nice flowers that attract bumble bees and expands at a manageable pace. If it goes someplace unwanted, I've found it easy as pie to lift up and remove or relocate a chunk.

Then there's G. sanguineum - bloody geranium. I suppose it's called 'bloody geranium' because of its bright red roots, but it deserves the name for being a bloody nuisance. OK, I'll give it props for being fairly tough and semi-evergreen, but it's quite aggressive. Once it's established, it starts spreading far and wide via deep (relative to the size of the above-ground plant) and thick roots.

Even small blood geranium clumps put down deep roots before they start spreading laterally.

Try to remove the plant and those roots tend to snap (at least when you're pulling them from sticky, heavy clay - sand or loam might be a different story). Leave any bits of roots in the soil and the plant will reemerge to laugh at you behind your back. There are places where I've dug wide holes 10 inches deep trying to get all the root fragments and the plant still pops up after I've backfilled or jumps up somewhere nearby. (I think it also spreads a bit by seeding, though fortunately the seedlings show up near the parent plant and the self-seeding has not been rampant.)

Meanwhile, I'm loathe to plant anything else where I've tried to evict the bloody geranium, because I worry that the geranium will pop up again and I'll have to dig up the whole area, damaging the new plant.

So right now, I have a number of holes and bare spots in the garden where I'm just waiting for the bloody geranium to re-emerge so I can dig up another missed root. I suspect this will continue for months. At least.

Ajuga genevensis returns after a weeding attempt
Ajuga genevensis after I tried ripping it out last winter. Clearly, I failed the first time around.

Ajuga genevensis is in the same category. Well, except that the roots don't go as deep and I haven't tried ripping out (yet) as many times as the bloody geranium.

Still, from the picture above, you can see that it hasn't been impressed by my eviction efforts. I thought I'd torn out a rather large, thick patch of A. genevensis last winter, but clearly all I did was prune it.

Once I had praised A. genevensis for being less aggressive (and more evergreen in Tennessee) than the typical Ajuga (A. reptans) that you usually find at plant nurseries. It's true that A. reptans spreads a bit faster and less predictably, but I've found all the Ajugas are challenging to remove through hand pulling.

I hope my experiences save some other gardeners time, effort and hair-pulling.

Meanwhile, I continue to evaluate groundcover alternatives, focusing on natives. As I mentioned in a recent post, I think that effort is bearing fruit.

I'll keep observing and plan to post an update either at the end of this year or next spring with an overview of the best groundcover candidates so far.

How about in your garden? Have you planted anything aggressive that you later regretted? If so, did you succeed in evicting it or have you given up and simply found a way to live with it?


Follow Aaron Dalton on Feedio

Tuesday, April 18, 2017

Some disappointments - rose verbena, toad lily, epimediums and partridge berry

I recently wrote about a couple of native groundcovers - golden groundsel and rose petty - that have impressed me with their performance.

(That doesn't mean I won't change my mind with a few more years of growing experience under my belt. That's happened before many times. But right now, color me impressed. And I like to think that I've learned to wait at least a little longer before passing snap judgments.)

Anyway, it's not all sunshine and roses in the Garden of Aaron.

I've been forced to face some disappointments this spring.

And since one of the main goals of my blog is to help others learn from my mistakes (and successes), I thought I'd share these disappointments with you:

Rose verbena bites the dust after just a single year
Rose verbena (Glandularia canadensis) not looking its best

Rose verbena, Glandularia canadensis - Relatively easy to find at local nurseries (though typically in the form of the 'Homestead Purple' cultivar...which may or may not actually be a hybrid), I'd heard warnings that rose verbena liked good drainage and could die if forced to overwinter in heavy, wet clay soil (which I've got in spades).

Interestingly, rose verbena seemed to survive our relatively mild winter without too many problems.
It even stayed somewhat evergreen and started blooming early in the spring. I saw a swallowtail butterfly nectaring on one of the plants, which made me happy.

But soon, one by one, the rose verbena plants started turning brown and crispy. I'm calling this a failure and assuming either (a) it's a very short-lived perennial (practically an annual) or (b) it needs much better and lighter soil than I can provide.

It's a shame, because I've been trying to find effective, native groundcovers, and rose verbena had some appealing characteristics - it's fast growing, semi-evergreen in zone 7, heat and drought tolerant, and has a long bloom season. Unfortunately, it doesn't seem to have the toughness or longevity I need in a groundcover.

Don't see anything here?
That's because I mowed down the old Epimedium foliage a month or two ago and the new slow-to-emerge foliage and flowers got chomped by something (probably a rabbit). Which is a little odd, since the rabbits never bothered Epimediums much before...

Epimediums, fairy wings, horny-goat weed - I'd had good luck with a hybrid called x perralchicum 'Frohnleiten'. In fact, I came to like this herbaceous, evergreen-to-semi-evergreen groundcover so much that I featured it on its own blog post in May 2015.

Most sources recommend cutting off old Epimedium foliage before the new foliage emerges. In years past, I done this with bypass pruners, but as the patch grew a bit larger, I decided to try mowing down the old foliage this year.

I don't know if the mower was to blame, but the new flowers and foliage seemed slow and sparse to emerge this year. I was just starting to see a fair amount of foliage when something - I think a rabbit - came and devoured everything.

That's interesting, because in years past, the rabbits have seemed completely disinterested in Epimedium. Even before my Epimedium displayed a vulnerability to herbivores, I had soured a little on it. The flowers are pretty, but short-lived and rather inconspicuous. It grows slowly, which can be a good thing (you won't have to worry about it conquering a garden bed while your back is turned), but it also means that you'll be waiting a loooooong time for this groundcover to cover some ground and start displacing weeds.

Although 'Frohnleiten' has grown fairly well here in Middle Tennessee, the other Epimediums that I tried (x warleyense and x versicolor 'Sulphureum') have not fared nearly as well. They haven't been growing as long and I've heard that Epimediums are notoriously slow to settle in, but Sulphureum disappeared during last year's autumn drought and hasn't been seen since. The warleyense hybrid hung in there, but barely sent up any new foliage so far this spring, and what did emerge was eaten just the same as the 'Frohnleiten'.

I haven't given up quite yet on my Epimediums at this point. If they recover from the rabbit attack and send up new foliage, I'll be tickled pink.

And if that does happen, next spring I think I'll just leave the old foliage to decompose naturally without cutting it at all. I tried that last year, and even though the rough, leathery, tattered old foliage detracts a bit from the freshness of the flowers and new leaves, it also provides a contrast that makes it easier to see the bronzy new foliage on 'Frohnleiten' (which can otherwise be a challenge to notice against a background of mulch or dirt) and also I suspect that the old foliage deters herbivores from chowing down on the new growth.

Still, even if my Epimediums do stage a comeback, I can't imagine getting any more at this point, and I'd only consider recommending them for a very small garden where the slow horizontal growth rate would be an asset, or a larger garden where groundcover needs were somehow minimal.

Partridge berry (Mitchella repens) does cover ground, but it's a pretty subtle plant. You might easily overlook it in a large garden. And the ultra low-growing foliage doesn't block all the weeds.

Partridge berry, Mitchella repens - I've gone back and forth on this plant. Much like with Epimedium, one of my main complaints would be that it's a sloooooow spreader. And the leaves are tiny. Which means that even where it does spread, weeds can still force their way through.

A close-up on the partridge berry. Note how the small weed - probably some type of Oxalis - has poked its head through the partridge berry foliage without any difficulty. Having a ground-hugging plant like partridge berry has some advantages - there's no need to chop down old stems or seedheads, you won't have to worry about it swamping any nearby plants - but it does limit the weed-blocking role it can play in the garden.

That said, I don't want to be too harsh on this native plant. It blocks some weeds. It's essentially evergreen in Middle Tennessee. It had a few tiny flowers last year, though if it produced any berries, I didn't notice. I certainly wouldn't discourage anyone from using this, nor am I contemplating removing mine. In fact, I just added another clump of this plant to the garden this spring.

But I'm a bit disheartened at its slow spread and imagine it will be many years (if ever) before I have a nice, thick, noticeable clump like this.

Again, if you have a very small garden or a garden with only a small patch of bare ground to cover, this might be just the ticket.

PS - Partridge berry is so diminutive that I've often wondered how it avoids getting smothered by leaves in its native woodland habitat. According to Brooklyn Botanic Garden, it generally grows on steep slopes where fallen leaves slide away. If you have it growing on flat land (like I do), you might need to brush away leaves to let it see the light.

Chomped toad lily.

Toad lily, Tricyrtis hirta 'Miyazaki' - Bought this one on a whim during a nursery visit this spring. Turns out that it makes excellent rabbit food. (Or food for some other herbivore, but the signs point to a bunny.)

How about you? Any groundcover / perennial disappointments recently? Or happy surprises? 😎


Follow Aaron Dalton on Feedio

Monday, April 10, 2017

Alabama croton - a marvelous, rare shrub

The Encyclopedia of Alabama calls Alabama croton (Croton alabamensis) one of the rarest shrubs in North America.

So I felt pretty lucky to see it in person on a recent trip to the Huntsville Botanical Garden:

One of the things I had heard about Alabama croton was that the autumn foliage took on shades of electric orange. As you can see, the plant seemed to be fully leafed out in its new spring foliage, but I was able to find a lingering orange leaf, and it still looked fantastic on April 1st. I think the green foliage is pretty awesome too!

I realize that this photo would be more useful if it had a person in the picture for scale. Sorry about that. Please take my word for it - this plant (or clump of plants?) was about 7 feet tall at its highest point by perhaps 12 feet wide. As you can see, the foliage is pretty dense. I'm glad I saw this shrub in person, because the photos I'd seen online made it look as though the foliage was very sparse, but here I'd say the foliage is dense enough to offer good screening potential. 

All in all, I was sufficiently impressed that I'm going to try adding an Alabama croton to my garden this autumn. (I try to plant most shrubs and trees in autumn.)

I've seen photos online (from NCSU) of the plant apparently thriving in Knoxville and Brooklyn, so I believe it should be able to take a Nashville winter without any problems.

PS - Deb at Deb's Garden really likes this plant too!


Follow Aaron Dalton on Feedio

Thursday, April 6, 2017

Good native groundcovers - Robin's plantain and golden groundsel

I've trialed a lot of groundcovers and made a lot of mistakes over the past 6 years in my efforts to find that magical plant that will cover ground and suppress weeds, but not be too aggressive/invasive or too much work to maintain.

Here are two promising evergreen / semi-evergreen candidates that have performed well so far. The fact that they are both native to this part of Tennessee is a big bonus.

Packera obovata, golden groundsel, fully evergreen through this past (relatively mild) winter. 
(I tried growing another Packera - P. aurea - last year, but it did not seem as tolerant of heat and drought, even in partial shade, as P. obovata.)

Erigeron pulchellus, Robin's plantain As you can see, the Robin's plantain gets a bit more tattered over the winter compared to the golden groundsel. Still, in my experience over the past few years, the old foliage tends to decay naturally without any intervention on my part, and the plants will look much better soon as new foliage appears. (Yes, the flower head here looks a little strange...a bit like a conjoined twin. That's not the normal flower appearance, as you can see below, but it's not that uncommon either with Robin's plantain.)

I think golden groundsel needs partial to full shade in hot summer climates like Tennessee, and Robin's plantain also thrives in some shade, but I'd like to try it in sunnier spots too to see how it performs. It's relatively easy to divide and transplant Robin's plantain in early spring or early autumn, but I've learned the hard way that divisions are unlikely to survive if you wait too long in either season.


Follow Aaron Dalton on Feedio

Tuesday, April 4, 2017

Not your typical tulip (It's like a dream!)

'Dream Touch' tulip from Brent and Becky's Bulbs


Follow Aaron Dalton on Feedio