Putting on a show this week in the garden are the Living Stones. No, not Mick, Keith, and Ronnie, but the horticultural Living Stones, Lithops aucampiae. Our oldest patch starts flowering in early to mid November each year, growing beautifully under an overhanging rock.
For all the articles about how difficult they are to grow, and how they won’t take any frost, we’ve found it all to be completely fake gardening news. These were started from seed in 2018, and have now survived 11F in the ground with no ill effects. We have them planted in a soil mix of 50% Permatill gravel, 25% native sandy loam, and 25% compost, with an open exposure to the south.
We added two more species (L. hookeri and L. lesleii) to the garden almost two years ago and they have thrived equally as well. Sounds like the myth about Lithops being difficult to grow and not winter hardy is completely busted.
We love it when people tell us that certain plants won’t grow in our climate. As gardening contrarians, we thrive on proving gardening experts wrong. Below is a great example–our combination of Globularia repens (Spain, Italy) and Acantholimon halophilum (Central Turkey) thriving in the dryland crevice garden. Both have sailed through out rainy, humid, hot summers, and are now enjoying the cooler temperatures of fall.
Looking lovely at JLBG now is the purportedly tropical vine, Combretum indicum. Native from a wide range of Southeast Asia, Rangoon creeper is a woody vine that’s shockingly winter hardy, as our plants sailed through last years 11 degrees F–despite it usually being listed as a Zone 10/11 plant.
The flowers usually open white, age to pink and then red, but this year, they have opened red–we’re not sure why. The tubular flowers are a favorite of long-tongued moths. It has grown much slower for us than it would in warmer climates, since our plant dies to the ground each winter. This year, our three year old plant has already returned to 8′ in height.
The North American native Thuja plicata ‘4Ever’ is looking particularly stunning in the garden this summer. Of all the forms of Thuja plicata we’ve trialed, this is undoubtedly the brightest. Reportedly maturing at 12′ tall x 3.5′ tall, I’m left to wonder what they used the measure the size. Our 4 year old specimen is 5′ tall x 5′ wide. Based on the current growth rate, we’d expect 12′ tall x 12′ wide in 10 years, so if you’re looking at “forever”, I’d probably put these on 15-20′ centers.
Juniperus x pfitzeriana ‘MonSan’ is looking quite exceptional in the garden. Since we live in the community of Juniper, NC, we thought we should have a significant collection of the our namesake genera. This Monrovia Nursery introduction, which is a hybrid between the Asian Juniperus chinensis and the Eurasian Juniperus sabina, is truly stunning. Although it’s marketed by the introducer as maturing at 3′ tall x 4′ wide, our six-year-old plants are 3′ tall x 12′ wide. Could someone be trying to trick you in to buying many more plants that you actually need…hmmm? Hardiness is Zone 3b-8b, at least.
With what seems to be an endless array of Hydrangea paniculata cultivars entering the market, July has turned the garden into a snow white scene. The Asian Hydrangea paniculata was first published as a new species in 1829, but was not grown in the Americas until Arnold Arboretum director, Charles Sargent brought back seed from an 1892 expedition to Japan. That original plant, now, 131 years old, measures 16′ tall x 25′ wide. I’m not saying you need to plan for your Hydrangea paniculata to reach 131 years old, but the average of a house in the US is 46 years, so logic says we should at least plant for a 50 year mature size.
Below is our clump of Hydrangea ‘Rensun’, which is marketed under a completely different name, Strawberry Sundae. The introducers of this lovely clone tout this as maturing at 5′ tall x 4′ wide, but our 6 year old specimen is already 7′ tall x 11′ wide. Based on that growth rate and the mature size of the species, I’d expect it to reach 14′ wide x 22′ wide in 50 years. It’s truly fascinating why it’s so difficult to for plant breeders to get more accurate measurements before these plants are introduced to market. One can only imagine the maintenance problems caused when you locate plants based on the size given on the plant tag, only to have the plant get 2-4 times as large as your space allows.
Here’s another of those plants that virtually no one has either grown or even knows about. Handelia trichophylla is a little-known monotypic member of the aster family (Asteraceae). Not only does it have hairy, silver foliage, which usually spells certain death in our summers, but it hails from the “stans”, which include the low rainfall countries of Afghanistan, Kazakhstan, Kirgizstan, Pakistan, Tadzhikistan, Turkmenistan, Uzbekistan, and Xinjiang. Our particular plant is from a seed collection in Tadzhikistan.
We would not typically expect anything native to the “stans” to survive in the hot, humid Southeastern US, but this is why we experiment, and why we create unique habitats and microclimates in our garden. In this case, Handelia has thrived for four years in our crevice garden, where it grows in a soil mix of 50% Permatill.
We were thrilled to have a great flower show this year on the most winter hardy honey myrtle we grow, Melaleuca ‘Wetland’s Challenged Mutant’. This introduction from Desert Northwest, is either a selection of Melaleuca paludicola, or a hybrid with that species. Most of the other “hardy” melaleucas (formerly, Callistemon) died to the ground this year, but this clone of the alpine honey-myrtle from Southeastern Australia didn’t even suffer burned foliage, and flowers buds were obviously fine. Our 11 year old plant is 7′ tall, and has endured two single digit winter temps; 7F, and 9F. Hardiness Zone 7b-10b.
Looking really lovely in the garden now is Juniperus x pfitzeriana ‘Daub’s Frosted’. This selection of the hybrid between Juniperus sabina and Juniperus chinensis was introduced by Oregon’s Mitsch Nursery in 1987. Our 18″ tall patch has spread to 10′ wide in less than 5 years. All of those trusted on-line sources say it matures between 5 and 6′ wide…Ooops.
In 60 years of gardening, I’ve yet to seen a nursery that offers Acanthus spinosus, who actually has the correct plant. 100% of everything in the commercial trade is actually a hybrid of Acanthus hungaricus and A. spinosus, which looks nothing like the true species.
Even authoritative on-line reference sites which should know better, all show the wrong plant, identified as Acanthus spinosus. To make matters more confusing, there is also a hybrid of Acanthus mollis x spinosus in the trade, known by the name Acanthus x spinosissimus. The more prevalent hybrid I mentioned earlier has yet to get a published notospecific name. Perhaps the name Acanthus x spinaricus would make sense.
Below is our plant of the true Acanthus spinosus this month, grown from seed wild collected in Greece, where it grows natively. Perhaps one day, we’ll have enough to share. Since no one has grown the correct plant, the reported hardiness data you find on-line and in reference books is worthless. We’d guess Zone 7a-9b, at least.
I’m betting that even the most seasoned plant collectors probably haven’t grown or even heard of Urophysa henryi. This odd generic member of the Ranunculaceae family hails from China, where it can be found only in a very few scattered populations, hanging out from cliff-side karst rock fissures in Guizhou, Sichuan, Western Hubei and into Northwestern Hunan.
Urophysa henryi is very closely related to the highly prized, but rather difficult to grow, rock garden plant, Semiquilegia adoxoides. I was particularly interested to read in a 2021 Chinese research paper, “In field observations and laboratory experiments, we found that U. rockii and U. henryi can not survive outside the karst limestone, which indicated that the karst limestone plays a significant role in their growth and development.” This is why you never send a botanist to do a horticulturist’s job!
In our garden, sans the Karst limestone, it has thrived in our rock garden, not blinking this year at 11F. The 4″ tall x 6″ wide evergreen clumps of columbine-like foliage are topped with clusters of small, outfacing white flowers, which resemble our native Isopyrum biternatum, Like Isopyrum, Urophysa flowering starts for us in early January, and continues through March. We think these are an outstanding addition to the winter garden and are going to do our best to get these propagated to share before words gets out that they can’t be grown in cultivation.
One of the nice surprises this winter has been the performance of our hybrid Magnolia grandiflora x Magnolia coco. This 2019 seedling came through the recent 11 degrees F looking great, despite half its parentage being rather tender.
While Magnolia grandiflora is certainly winter hardy here, the other parent, Magnolia coco is “reportedly” not hardy. Magnolia coco is a small tree/shrub hailing from Vietnam, Southern China, and Taiwan. Those reputable on-line sources consistently write that it isn’t hardy north of Zone 9. Well–hmmm!
The bottom image is our plant that has been in the garden since 2003…that’s 20 years. Yes, after 11F, the foliage is brown, but the stems are fine and it will re-flush well in spring. We can’t wait to see the flowers on the hybrid, which is still a few years away from being old enough to have sex.
Magnolia grandiflora x Magnolia cocoMagnolia cocoMagnolia coco after 11F
11 degrees F was a bit more than our clump of Massonia depressa had hoped for. Although the cold temperatures burned a bit of one leaf, it not only survived, but is now in full flower. That’s pretty amazing for a South African bulb that Wikipedia authoritatively states “does not tolerate freezing temperatures”. Rock on!
One of the nice surprises after our 11 degree F freeze was how well our Escallonia ‘Iveyi’ fared. Few people on the US East Coast are familiar with these South American woody members of the Escalloniaceae family.
Escallonia ‘Iveyi’ is actually a hybrid that originated at the UK’s Caerhays Castle, where it was discovered as a seedling between Escallonia rosea and Escallonia rubra. Our plant should mature at 10′ x 10′. In mid summer, this amazing selection is smothered in fragrant white flowers.
All the literature we’d been able to find, indicates it is only hardy to 14 degrees, but that’s another reason we don’t let our plants read gardening books or browse the Internet. Our plant was grown from cuttings from an old specimen at the SC Botanical Garden in Clemson.
This week, we fielded a call from our garden staff that there were large yellow jacket (Vespula maculifrons) nests in several arborvitae near where they were working. Knowing how aggressive and toxic the stings of these native vespid wasps can be for humans, they had requested help in getting the nests eliminated.
When Patrick arrived to check out the problem, he noticed that instead of finding nests, the yellow jackets were actually feeding on the arborvitae. Since this species of arborvitae was currently in the midst of pollen and cone production, there also appears to be some type of resin being exuded at the same time, which is a delicacy for the yellow jackets.
We estimate there were between 100 and 200 yellow jackets per plant. Because they were busy feeding, they had no interest in us, despite our close up study of their behavior. Our entomologist, Bill Reynolds, who had observed this phenomenon before with vespid wasps and arborvitae, showed us that we could actually touch the yellow jackets without drawing their ire. This is certainly not the case if you’ve ever been anywhere near a yellow jacket nesting site.
The other interesting phenomenon is that despite being Eastern US natives, the yellow jackets were only interested in the Asian arborvitae species, Platycladus (Thuja) orientalis. Growing adjacent was the East Coast and West Coast arborvitae, Thuja occidentalis and Thuja plicata, but neither attracted a single insect. This is another nail in the coffin of that oft repeated myth that only native plants feed native pollinators. One of many lessons here, but it’s especially important not to spray first and ask questions later.
Thuja orientalis ‘Beverly Hills’ Thuja orientalis ‘Beverly Hills’ Thuja orientalis ‘Beverly Hills’
