Wednesday, November 18, 2015

Last of the Bloomers

I think it's almost "lights out" for the flowers in the Garden of Aaron this year.

Temperatures are forecast to drop in the coming days (40s for high on Sunday, lows in the 20s), but up to this point, unusually warm autumn weather to date has allowed some brave bloomers to strut their stuff right into Thanksgiving territory.

Mexican sage, Salvia leucantha, has bloomed for months from summer to late autumn. In recent weeks, it became a magnet for bees and other pollinators.

Sweet alyssum (Lobularia maritima), also a long bloomer, very popular with mini pollinators (hoverflies, etc.)

Most of the hardy geraniums stopped blooming long ago, but 'Rozanne' hybrid geranium carries on with a few last flowers. Unfortunately, Rozanne doesn't have the same winter presence as some of my other favorite cranesbill geraniums. Where Geranium sanguineum and Geranium cantabrigiense seem more or less evergreen here in zone 6/7, 'Rozanne' has acted behaved like a true herbaceous perennial, dying back to the ground each year. 

This unknown Camellia sasanqua has had a great year. As you can see, if you pick a camellia with open, single flowers, you'll give the bees a banquet!

A few of the flowers on this group of reblooming azaleas have been blasted by frost, but the shrubs are still putting on a magnificent show!
OK, no flowers here, but the fall foliage on this Virginia creeper (Parthenocissus quinquefolia) certainly shines on its own.

No flowers here, but I love the pop of the red chokeberries (Aronia arbutifolia) against the variegated aucuba (Aucuba japonica) in the background.

Thanks for reading and commenting this past year.

I'll continue to post in the weeks and months ahead, though most likely at a more lugubrious pace than during the growing months, but I do look forward to sharing information with you on plants I've added to the garden this fall, seeds I'll be winter-sowing and so forth.

Best wishes to you all (in the Northern hemisphere) for a warm and cozy winter season. And to you in the Southern hemisphere... Happy Spring :)


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Tuesday, October 27, 2015

Feeling Crabby

After a couple days of rain, the lawn is verdant and the 'Sugar Tyme' crab apples are glistening like jewels...

Each crabapple is adorned with a raindrop...


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Monday, October 19, 2015

Cultivars vs. Straight Species -- Viburnum Dentatum / Arrowwood Viburnum

So where do you stand on the whole cultivar vs. species issue?

Here at Garden of Aaron, I grow three types of Viburnum dentatum (arrowwood viburnum), which is native throughout much of the Southeast, Midwest and Mid-Atlantic and up into New England.

Here is how the straight species looked in early October:

Here is the form of a Viburnum dentatum (straight species), growing in full sun and awful solid clay 'soil' (1st year in the garden)

Here's a close-up of the foliage, which I'd say still looks pretty darn fresh for early October!

Here is how the 'Pearl Bleu' cultivar looked at the same time:

Here's V. dentatum 'Pearl Bleu' -  as you can see, much of the foliage has folded in half and quite a few leaves have burnt edges.

And here is the 'Chicago Lustre®' cultivar, also on the same day:

By contrast, the foliage on the 'Chicago Lustre' cultivar of V. dentatum looks fresh, lush, healthy and deep green. 

Remember, these are all the same species - just different cultivars - growing in very similar conditions.

In fact, here's a side-by-side shot to show you that 'Pearl Bleu' and 'Chicago Lustre' are growing literally side-by-side. They're both on the northwest side of the house, which gets mostly shade all morning, but bakes in a surprising amount of sun on summer afternoons. In fact, I'd say 'Chicago Lustre' may actually get more of the afternoon sun and perhaps provides a bit of shade to its 'Pearl Bleu' companion.

'Pearl Bleu' on the left, 'Chicago Lustre' on the right. Both shrubs were planted at the same time. Both actually died back to the roots (after I stored them in the garage over the winter and shamefully neglected them), but 'Chicago Lustre' has clearly roared back more vigorously than 'Pearl Bleu'...

Interestngly, the straight species produced more fruit this year than either of the cultivars (although the berries on Chicago Lustre appeared to be larger and more plump than those on the species). All the Viburnum dentatum berries on the species plant and 'Chicago Lustre' have already been devoured by the birds. (I suspect that a mockingbird and a blue jay divided the ones on the species plant.)

I'm planning to add a few more V. dentatum cultivars to the garden this autumn (from Classic Viburnums nursery, which has an amazing selection of the genus), so perhaps I can report back in a year to give a comprehensive overview of the relative strengths of the different cultivars vs. the species.

Oh and then there's this little seedling that popped up on the corner of the house right near where 'Chicago Lustre' and 'Pearl Bleu' could have canoodled. I've transplanted it to someplace where it will have a bit more room to spread its wings...

I'm fairly sure that this is a Viburnum dentatum seedling. It seems to have taken the transplantation well. You'll notice that the foliage is lighter-green and has more of a matte finish, but otherwise seems just as clean and healthy as the 'Chicago Lustre' foliage. 

How about in your garden?

Do you like growing straight wild species plants or do you seek out cultivars?

Personally, in some cases I favor the straight species and in other cases I see the merits of cultivars.

For instance, I chose to grow the 'Miss Huff' cultivar of Lantana camara because it is supposed to have better cold hardiness than the species and I was worried that the straight species would not survive here in Tennessee. (Actually, I'm not sure one can even find a straight species Lantana camara at nurseries. The only ones I've seen for sale are different cultivars.)

With Viburnum dentatum, the jury is still out for me. I'd say that the species has done much better so far than 'Pearl Bleu', but I quite like the 'Chicago Lustre' cultivar.

In other cases - for instance with Echinacea purpurea (purple coneflower) - I only grow the straight species. For one thing, I've read that the species is tougher and has greater longevity than the cultivars.

The cultivars of many flowering plants are bred to have bigger, fancier, 'double' flowers. But if you garden to help the bees and other pollinators like I do, you're probably better off choosing a plant with simpler, single flowers. As says: "Most double flowers are of little use [to bees], as they're too elaborate. Some are bred without male and female parts, while others have so many petals that bees can't get to the nectar and pollen. So single dahlias are popular with many bees, while doubles are usually ignored."

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Monday, October 12, 2015

What a Difference Six Months Makes -- Lantana camara 'Miss Huff'

This is my first year growing Lantana camara, a flowering plant from the tropical regions of Central and South America.

It's my understanding that L. camara grows into a large shrub in its home range or other tropical environments, but here on the border of USDA zones 6 and 7, it's only marginally hardy. It's my understanding that it will die to the ground this winter and (hopefully!) resprout in the spring. Even if it does act as a perennial here, I doubt it would get bigger than it did this year (about 2-3 feet tall and wide).

I chose the 'Miss Huff' cultivar because it is reportedly the most cold hardy L. camara available.

My wife was skeptical at first, which is understandable because the two plants we purchased looked like this when we first brought them home in April and stayed about the same size into May:

Lantana camara in spring 2015, first year in the garden

Today, they look like this:

Lantana camara in October 2015, still first year in the garden! These flowers have bloomed non-stop for months.

It took the butterflies a little while to discover the plants, but especially in late summer and into early autumn (August, September and October), the two L. camara plants have been aflutter with butterflies throughout the day.

Not only are the flowers pretty to people, but clearly they are the cat's meow to butterflies.
Hopefully, 'Miss Huff' will survive the winter and come back next year (I'll let you know!), but regardless these plants offer so much beauty throughout the summer and autumn that I'm planning to add a few more to the garden next spring. Even if they only behave as annuals, I think they'd still be worth having in your garden.

Lantana camara does seem to prefer a good bit of sun. The plant that was in a mostly sun setting flowered and grew a bit better than the one that received afternoon shade from a Vitex agnus-castus (chaste tree).

With just a bit of supplemental water early in the summer to help them get established, both plants proved extremely heat and drought tolerant. The flowers are self-cleaning (i.e., there's no need to deadhead) and the plants bloom profusely and cheerfully for months and months.

I do believe that L. camara is invasive in various tropical or subtropical parts of the world, including in parts of the U.S., especially along the Gulf Coast. In Texas, the problem seems to be limited so far to Austin and points south. In Florida, it is considered a Category I invasive as it displaces or hybridizes with native plants.

As far as I know, it is not considered at all invasive here in Tennessee. As I said, I think it's only marginally hardy here to start.

If you live in a warmer zone and feel you must have Lantana camara to feed butterflies, please look for a cultivar that is considered sterile or seedless.

Actually, per Clemson, I see that 'Miss Huff' is supposed to be sterile! Hooray!! This makes me feel even better about growing this cultivar. I also suppose it explain why I haven't seen any fruit on Miss Huff despite lots of pollinating action going on. Good deal.

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Monday, October 5, 2015

Soldiers on the Agastache!

These soldiers (OK, soldier beetles) like to make love, not war. Often, you'll see one (female?) beetle crawling around while another (male?) beetle hangs on its back (presumably) trying to mate.

The last couple of years, the soldier beetles did their loving on the 'Lemon Queen' sunflower, but when that plant suddenly and unexpectedly crashed this past spring (and was subsequently shovel-pruned), they moved on to other plants this year - primarily agastache (like this Agastache foeniculum), but also Sedum 'Autumn Joy'. When they are not getting it on,  I believe soldier beetles generally serve as important beneficial insects in the garden.

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Wednesday, September 30, 2015

Trip Report -- London Kew Gardens (3 of 3)

And now the final batch of photographic highlights from my August trip to Kew Gardens. Enjoy!

Panicum virgatum 'Shenandoah'

This looks like variegation, but I think it is the beginning of a process by which leaves yellow and then drop prematurely from Russian sage (Perovskia atriplicifolia). I've seen the same thing in my garden, although it tends to happen much earlier in the year in Tennessee, perhaps due to heat and drought stress?

Sorghum bicolor 'Texas Black' -- this plant had some serious height, and I could see it working nicely as an attractive temporary screen.

Symphytum (comfrey) 'Hidcote Pink'
The bees were buzzing all around this Tilia kiusiana (Kyushu linden)

Other pollinators also joined the Tilia kiusiana banquet...

Love the fact that you can buy vegetables at Kew!

I was mighty impressed with this 'Cos Dixter' lettuce. Looks tasty!

Finally, here's a look at the variety and beauty of student vegetable plots at Kew. I think it would be great if more botanic gardens had these sorts of sections to show that gardening is something accessible and intimately connected to people, rather than just an abstract aesthetic exercise.

Thanks for joining me on this visit to Kew. We may be bidding Kew a fond farewell, but I'm not done yet with my travel posts. 

Stay tuned -- or better yet, sign up for a free email subscription -- to make sure you don't miss more posts on London gardens and a visit to the Jardin des Plantes in Paris!

Monday, September 28, 2015

I Love some October in September! :)

Aren't October Skies beautiful?

I love our native 'October Skies' aster (Symphyotrichum oblongifolium) - and so do the many bees and other little pollinators that mob the profuse flowers.

Planning to add some more of these to the garden next spring...

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Friday, September 25, 2015

Boxwood Blight Rears its Head in Tennessee

Blight-striken boxwood in process of defoliating (photo via Oregon Department of Agriculture)

University of Tennessee has warned that boxwood blight - a fungal disease first spotted in the state in 2014 - could wipe out many of the boxwoods that are a mainstay in many residential landscapes.

I'll be honest. I've never liked boxwoods much. They seem boring and botanically 'inert' (except for the brief period in the spring when they flower and attract pollinators). If you prune a boxwood and leave the clippings on the ground, they turn an unsightly white/yellow but they don't actually decompose for many months. And boxwood foliage can get blasted here by winter sun and/or late freezes.

That said, it's a popular, tough evergreen mainstay in many residential gardens.

If the blight really does take its toll, what should home gardeners use as a replacement in Tennessee (and elsewhere)?

A dwarf version of our Southeast native Ilex vomitoria (yaupon holly) could be a good option. It looks similar and it's evergreen, although not especially cold hardy. I think most yaupons are only rated to zone 7 and we're right on the zone 6/7 border.

Any other ideas? 

We need more than one replacement, because monocultures tend to encourage the emergence and spread of plant diseases. I'm hoping we can use this as an opportunity to add more native plants to the garden that have wildlife value... 

PS - Stay up-to-date on the conversation with a free email subscription to Garden of Aaron...

Wednesday, September 23, 2015

Trip Report - London Kew Gardens (2 of 3)

Building on last week's post, here are more highlights from my August visit to Kew...

Many of the bamboo specimens at Kew Gardens looked like they were raring to burst through the black plastic barriers holding them back. This specimen of Fargesia nitida, however, seemed like it would be much better behaved in a garden setting.

Geranium x riversleaianum 'Mavis Simpson'

Usually, I think dwarf Ginkgo biloba cultivars look ridiculous, but I have to admit that this adorable 'Troll' won me over!

Another floriferous border overflowing with Helenium 'Wesergold'

A Japanese gateway adorned with balloon flowers (Platycodon grandiflorus)

Japanese rowan (Sorbus commixta)

Don't miss the final installment of my visit to Kew -- stay in the loop with a free email subscription to Garden of Aaron.

Monday, September 21, 2015

Weed Alert! Beefsteak Plant / Perilla frutescens

Perilla frutescens is a pretty weed, but apparently here in Tennessee, it's pretty toxic to cattle and other grazers. FYI, the shrub in the background is Viburnum dentatum 'Pearl Bleu'. The herbaceous plants covering the ground are mostly native columbine (Aquilegia canadensis).

Since I don't put mulch heavily or put down any weed-suppressing chemicals, I tend to have a lot of plants pop up in my garden beds.

Some of them are the usual weedy scourges (crabgrass, spurge, clover, oxalis, etc.), but sometimes there are plants I don't recognize and have never seen before.

Sometimes, these unknown seedlings can be exciting volunteers -- like my discovery of a Sassafras albidum seedling this summer! And I'm pretty sure that my Viburnum dentatum (arrowwood) shrubs have produced a seedling, which I'll try transplanting in the weeks ahead.

But then there are discoveries that initially seem exciting, but ultimately turn to disappointment.

Such is the case with the plant shown above. I thought it might be one of the Scutellaria (skullcap) native wildflowers. I've only seen photos of those plants online, so I wasn't sure what would look like in person.

Anyway, I had my doubts (the flowers from the Scutellaria photos looked much bigger than the blooms on my mystery plant), so I checked with an extremely helpful local expert (Amy Dismukes, UT/TSU Williamson County Extension Agent) and she identified the seedling as Perilla frutescens (beefsteak plant).

Now Perilla is native to Asia and unfortunately, it turns out that it is invasive in parts of the U.S., including Tennessee (according to the National Park Service).

So I ripped it out.

A closer look at Perilla frutescens (beefsteak plant, shiso) before it met an untimely demise at my hands

Could I have eaten it? I'm not sure. In parts of Eastern Asia (e.g., Japan, Korea, China and Vietnam), I believe that Perilla frutescens is used as an herb/seasoning. I'm pretty sure that I've eaten  the occasional shiso leaf (as Perilla is called in Japanese cuisine) as an accompaniment to sashimi or chirashi. It had a very strong, distinctive flavor - not unpleasant, but I can't imagine eating more than a few leaves at a time.

On the other hand, I presume/suspect that I was eating a Perilla cultivar that had been bred for edibility. University of Tennessee says that the plant is highly toxic to cows and horses, and in fact causes more cattle deaths in the state than any other plant.

Meanwhile, a Purdue University paper cites research showing that a chemical compound called a ketone (Perilla ketone, to be specific) may be the culprit as far as the toxicity is concerned. Interestingly, Purdue notes that this ketone was found in P. frutescens samples from Tennessee, but not in seed from Oklahoma plants nor in commercial samples from Japan.

What does this all mean? As I see it, there might be at least a few plausible interpretations of this data:

1) P. frutescens is evolving new chemical defenses here in North America.

2) Perhaps wild P. frutescens has always had chemical defenses, and the cultivated versions grown in East Asia had those defenses bred out of them by humans over a period of hundreds or thousands of years? In that case, perhaps the presence of the ketone in the Tennessee specimens is a reversion to a defense that had been lost? Wikipedia notes that wild North American shiso often has lost the fragrance that makes it a desirable herb and that these wild, weedy plants are not suitable for eating (due to the presence of the Perilla ketone).

3) Perhaps there is great variability in the species (the fact that seeds from wild P. frutescens plants in Oklahoma did not seem to contain this ketone lends credibility to this hypothesis) and it's luck-of-the-draw as to whether a given P. frutescens plant contains Perilla ketone or not.

So, would I personally nibble a wild Perilla frutescens plant growing in Tennessee?

No, I would not.

And since this is a weedy, exotic invasive plant in at least some parts of the U.S., should you (North American readers) come across it growing in your yard, field or garden, I'd encourage you to remove it.

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