Suckin’ Daphnes

I’ve been surprised to see the black swallowtails regularly enjoying the nectar of the summer-flowering daphnes…in this case, Daphne x napolitana ‘Bramdream’. Our plants are thriving, growing in our full sun rock garden.

Little Big Man

Most highly prized rock garden plants originated somewhere other than the Southeast US. One notable exception is Bigelowia nuttallii, or if you prefer common names, Nuttall’s rayless goldenrod. This fascinating plant resembles a whisk broom that just swept up a spilled bottle of mustard.

Named after English botanist/zoologist Thomas Nuttall (1786-1859), who lived in the US from 1808 until 1841, this fascinating plant, grown by rock gardeners worldwide, is native in only a few locations from Georgia west to Texas.

Bigelowii nuttallii makes a tight evergreen clump of needle-thin leaves, topped from mid-summer until fall with 1′ tall sprays of frothy yellow flowers…yes, those are actually flowers, but without the typical showy “rays”. Full sun for at least half a day, and good drainage are the key to success with this very easy native perennial. Hardiness is Zone 5a-9b.

Stingray in the Garden

We love the spineless Agave bracteosa ‘Stingray’ in the garden. We’ve had these dotted throughout the garden since 2017, and so far, with good drainage, they’ve handled our winters quite well, which is certainly not normal for a variegated century plant. This particular species prefers part sun to light shade. Hardiness is Zone 7b/8a and warmer.

Thyme Flies, Thymophylla Flowers

We are in love with the long-flowering Thymnophylla pentachaeta var. pentachaeta ‘Laredo Gold’, which graces us with masses of gold flowers from spring through fall, in our sunny, dry rock garden. This Patrick McMillan collection comes from a population in Texas. Not only is this short-lived, southwestern US native reseeding perennial great in flower, but the native Navajo Indians also used it as a drug for people who want to dream of being chased by deer….we are not making this up!

Baccharis-foliaged Beardtongue

We are enjoying the rare Penstemon baccharifolius this summer in our high/dry crevice garden. This species is native to limestone ledges up to 6,500′ elevation from the Edwards plateau in Texas south into Northern Mexico. This species hates our summer rains, and we had given up on growing this until we built our alkaline crevice garden a few years ago. Now it thrives, growing in 3′ deep Permatill gravel.

Baker’s Lily

We were thrilled to have Lilium bakerianum show up recently with a couple of flowers. This rare, dainty, woodland lily rarely exceeds 2′ in height. The arching stems are difficult to spot in the Chinese grasslands that they call home, unless you are lucky enough to catch them in flower. Lilium bakerianum, named after English botanist  Edmund Gilbert Baker (1864–1949), is quite variable, and as such is divided into five distinct varieties.

Our plants, which are Lilium bakerianum var. rubrum, are located at the top of our crevice garden so they are easy to appreciate when walking below.

More pricks

It’s been quite a floral extravaganza this spring in the dryland garden sections. Here are the latest of our flowering barrel cactus that have bloomed recently at JLBG. All of our cactus are growing outside without any winter protection in our zone 7b garden. The key for most is simply good soil drainage.

Coryphantha sulcata
Echinocereus coccineus
Echinocereus papillosus var. angusticeps
Echinocereus reichenbachii var. baileyi
Echinocereus stoloniferus
Echinocereus x roetteri
Echinopsis ancistrophora
Escobaria dasyacantha SB601
Escobaria vivipara var. neomexicana
Lobivia atrovirens var. ritteri
Lobivia haemantantha
Lobivia thionantha
Notocactus apricus
Notocactus floricomus
Notocactus x subluteus (submammulosus x roseoluteus)
Trichocereus 20-07 (‘Big Time’ x Iridescent Watermelon’)

Hot Ice Plants

Delosperma cooperi and Delosperma ‘Kelaidis’ have formed a lovely union in our crevice garden, where they grow in pure Permatill gravel. The key to growing ice plants in a hot, humid, rainy climate is excellent drainage.

Formanek’s Bellflower

The Greek bellflower, Campanula formanekiana has been superb in the crevice garden this spring. This amazing monocarpic (dies after flowering) species take three years to flower, and when it does, it puts on one heck of show. It’s namesake was Czech botanist, Eduard Formanek (1845-1900). We’re hoping for a good seed set. Hardiness is Zone 7a-9a, at least.

The Crevice is “Woke”

The crevice garden has “woke” for spring, with early flowering plants in full gear. Here’s a shot of one small section, featuring Delospema dyeri and Iberis simplex (taurica). We hope you can visit in person for the second weekend of our spring open house, May 6 – 8, 2022.

Asparagus kissin’ cousin

Ok…raise your hand if you’ve grown Aphyllanthes monspeliensis? This odd, monotypic (only member of the genus) is actually a member of the Asparagus family. Hailing from France south into Northern Africa, Aphyllanthes can be found growing in hot, dry, sandy soils, where it produces an amazing spring show of blue flowers on a 1′ tall clumper. The species name “monspeliensis” is named after Montpellier, France, where it grows naturally. Our plants are thriving in our crevice garden, putting on a superb flower show in mid-April.

Mukdenia – a Rocky Sax

Mukdenia is an odd monotypic genus in the widespread Saxifrage family, along with cousins heuchera, tiarella, and the namesake saxifraga. The odd genus name honors the former city of Mukden in Manchuria, which is now known as Shenyang. Mukden was the site of the largest modern day battle, prior to WWI. In case you missed it, the final score was Japan 1, Russia 0.

Several on-line sites, including that purveyor of accuracy, Wikipedia, proclaims there to be two species of Mukdenia, which is sadly incorrect. Although I’m sure Mukdenia rossii would like a sibling, one simply does not exist. I think of Mukdenia like Smucker’s…with a name like that, it has to be good…and it is.

Mukdenia naturally resides in China and Korea, where it can be found in some rather inhospitable places. I had to laugh when I read countless on-line articles that repeat the myth that mukdenia needs water during summer drought. It certainly doesn’t mind summer water, and will probably look better as a garden specimen with some irrigation. My first encounter with mukdenia in the wild was in fall 1997 on South Korea’s Mt. Sorak, where it thrived, growing in the rock cracks of a nearly vertical cliff (below)

Mukdenia in situ, Mt. Sorak, Korea

When we built our concrete crevice garden, mukdenia was one of the first plants I wanted to plant to see if it would mimic what I had seen in the wild. Below is our 2017 planting of Mukdenia rossii ‘Karasuba’ in late March/early April 2022, as it emerges in flower. The foliage continues to expand around the flowers. Our plants get 3-4 hours of sun each morning, then shade the remainder of the day. Winter hardiness is Zone 4a-7b.

Mukdenia rossii ‘Karasuba’ in crevice garden – late March
Mukdenia rossii ‘Karasuba’ in crevice garden – early April

Deliciously Succulent – Bergeranthus

The South African (Eastern Cape) Bergeranthus vespertinus has been absolutely fabulous this late winter/spring season. Here it is growing in one of our rock gardens, where it is mostly protected from winter moisture. (Hardiness Zone 7b and warmer…at least)

Stock Split

Not only did we have 100% survival on our living stones (Lithops aucampiae ssp. koelemanii) in the garden, despite low temperatures of 15-16 degrees F, but they are now in the process of splitting, which is sort of like giving live birth. Splitting happens after flowering, and followed by a subsequent dormancy. The plant divides and the new plants absorb the of the old foliage…sort of like The Blob movie. We were fortunate to catch the process visually for the first time this week.

Lithops aucampiae ssp. koelemanii

Finally, a ferner adapts

Since ferns are one of the groups on which we focus our ex-situ conservation efforts, we have collected a huge number of species and selections from around the world. One that has continually frustrated us is the miniature rock fern, Asplenium trichomanes. Although this small gem is native to every continent except Antartica, we have struggled to keep it alive.

In our travels, we have collected it from Europe to Africa, but have also managed to kill all of those collections in the garden. Since our first attempt in 2004, we have now killed Asplenium trichomanes 16 times. We believe, however, in the late JC Raulston’s mantra, “Unless you are killing plants, you aren’t growing as a gardener.” The key is how many times do you continue to try before giving up?

We’re pretty stubborn as long as we feel we keep learning from each failure. Our latest accession of this species, which came as spores from Russia’s south coast, is actually thriving in our crevice garden, where the pH is north of 8.0. It seems that the crevice habitat is the answer.

Long-leaf Buckwheet

We admit to a long-standing case of buckwheat envy. Every visit to the worlds great rock gardens, such as the Denver Botanic Garden, leave us lusting to grow the rock garden genus, eriogonum. We’ve killed many members of the genus, since they truly hate our humid and wet summers. Even our crevice garden was no help in keeping these alive, even including our reportedly easy-to-grow Appalachian native, Eriogonum allenii. After almost giving up several times, we can finally declare success with the Texas native Eriogonum longifolium, from our East Texas botanizing expedition. Here’s our clump in full flower, and quite happy in one of the rock garden sections. Granted, it’s not as stunning as some of the species that thrive in Denver, but hey, we can now check that genus off the list.

Eryngium longifolium