We have been very impressed with the very narrow selection of our East Coast native arborviatae, Thuja occidentalis ‘Brobeck’s Tower’. This has been in the garden now for 4 years, and is 6′ in height and just over 1′ in width. This seedling selection was made by Sweeden’s Anders Brobeck, where the same plant takes 20 years to reach this height, due to a lack of summer heat.
We can’t imagine there are many people who grow cast iron plants from seed, but we have found the results quite fascinating. Below are a couple of our seedling which we found good enough to name. Neither has been divided yet, and are still under evaluation, but we think they have good potential.
Aspidistra ‘Bright Lights’ is a 2015 seedling from Aspidistra ‘Okame’ and has a similar variegation pattern, although it has more white banding than its parent.
Aspidistra ‘Illumination’ is a 2016 seedling of Aspidistra ‘Sekko Kan’, and inherited the white tips from its mama, but has also pickup up more streaking that wasn’t present in the preceding generation, so perhaps it outcrossed to a nearby streaked parent. If you’re interested in trying this yourself, the seed are found in a 1-2″ wide green ball at the base of the plant now. The seed should be mature in the next 4-6 weeks.
We were thrilled to see most of our plants of Trichocereus ‘Love Child’ come through the 11 degrees F unscathed. We hope to have enough of these in the next year or two to share. We had long wanted to grow and offer some of the ridiculously large flowered, tacky colored tropical trichocereus cactus, but they simply had no winter hardiness.
Enter our former volunteer curator, Mike Papay, who had the same idea, but was more determined to make it happen. Mike worked with Trichocereus bruchii, and the resulting second generation plants yielded one he named Trichocereus ‘Big Time’.
He created another winter hardy hybrid using Trichocereus bruchii and Trichocereus thelogonus that he named Trichocereus ‘Iridescent Watermelon’. We subsequently crossed both of Mike’s hybrids together to create a seed strain we named Trichocereus ‘Love Child’. Below is one of our garden plants after enduring 11 degrees F. Below that is the same plant in flower last spring. Hardiness zone 7b to 10b.
In 2006, NC plantsman, and our long time customer, Graham Ray of Greensboro, emailed to see if we were interested in a dwarf Asaparagus densiflorus (Sprengeri) fern that he grew in his rock garden, and had been winter hardy for several years in his Zone 7a garden.
We had already worked with several asparagus species for years, and have a great fondness for the ornamental potential of the genus, so of course, we jumped at the opportunity. We were perplexed, however, how a dwarf version of the marginally hardy Asparagus densiflorus could have survived in Greensboro, which is a 1/2 zone colder than our garden south of Raleigh.
Despite our skepticism, we planted our new treasure in fall 2006, which thrived here, despite our winter hardiness concerns, not blinking during three upcoming single digit F winters. A few years later, we sent a plant to our friend Hans Hansen at Walters Gardens in Michigan for further testing. Despite their winter temperatures well below 0F with no snow cover, it thrived there also. What was going on, we wondered, since this simply shouldn’t be possible.
Our mystery was finally resolved this summer when taxonomy researchers from the University of Georgia, working on the phylogeny of the genus Asparagus, learned of our extensive collection of Asparagus species, and came by to take samples for their research. This fall, we got word that our dwarf plant which we had named Asparagus ‘Graham’s Cracker’, was in fact not a selection of the common hanging basket species, Asparagus densiflorus, but was instead a seedling of the Zone 4 hardy Asparagus cochinchinensis.
As we re-traced the plants origin, it turned out that Graham had purchased the plant here at Plant Delights, as a dwarf seedling he found in one of our sale house flats, which our staff had failed to notice.
Above is a photo of a mature plant of Asparagus ‘Graham’s Cracker’ at JLBG, which has finally reached a whopping 15″ in height…a perfect plant for the rock garden or in larger bedding schemes. Like the species, the fall foliage is a brilliant gold.
And here’s mama, Asparagus cochinchinensis ‘Chuwang’.
This is a very good year for the annual winter fruit show on Rohdea japonica (sacred lily). The attractive berries remain until early March, when they begin to drop. Although seed from these cultivars do not come true, you’ll always end up with an interesting variety of offspring.
In 2014, we decided our goal for the years’ century plant breeding project was to see how large a Zone 7b winter hardy agave we could create. We had seven agaves flower that year, but only two had the epic proportions we required.
One of those was a selection of Agave x protamericana from a Yucca Do collection in Northern Mexico. By the time of flowering at 15 years of age, it had reached 5′ tall x 9′ wide.
Agave x protamericana and Agave americana are the two largest blue-foliaged agaves, but only Agave x protamericana is winter hardy for us, here in Zone 7b, since it also has some ancient genes from the slightly hardier Agave asperrima, which adds slightly to its winter hardiness. You can distinguish the two plants by feeling the back of the leaves. Agave americana has smooth leaf backs, while Agave x protamericana has sandpapery leaf backs. The largest size listed for Agave americana in Howard Gentry’s Agaves of Continental North America, is 6′ tall x 12′ wide.
At the same time we had a blind flower shoot on our giant Agave x pseudoferox ‘Bellville’. Agave x pseudoferox is another ancient Mexican hybrid in need of a DNA workup. We think its probably a hybrid of Agave x protamericana with Agave salmiana var. ferox and possibly Agave gentryi). Commercially, it’s usually called Agave salmiana var. ferox, which is similar in appearance, but with absolutely no winter hardiness.
Prior to full flowering at 15 years of age, our giant specimen of Agave x pseudoferox ‘Bellville’ had reached a mature size of 4′ tall x 8′ wide. We were able to make the cross prior to it fully flowering, by using something we mentioned above that we call “blind shoots” or boners.
Being monocarpic plants, the rosettes of most agave species die after flowering, but side shoots are an interesting phenomenon we see on all of our Agave x pseudoferox cultivars and hybrids. These “blind shoots” emerge from underground stolons instead of from a rosette. They are much shorter than normal flowering shoots which emerge from the rosettes (2′ tall vs. 20′ tall), and they have no impact on the life expectancy of any of the rosettes.
In the case of Agave ‘Bellville’, our plant began producing blind shoots five years prior to the clump producing a full size, rosette-based flower stalk. The beauty of blind shoots is that they breed and pass along characteristics of the parent without the need for a tall ladder.
We gave our hybrids the seed strain cultivar name, Agave ‘Bluebell Giants’. From these, we selected 23 clones, which were planted in the trial fields in 2016. Of those, only 4 survived our subsequent trials for winter hardiness.
Our best and most winter hardy seedling from the cross pictured below is now 6 years old in the garden. We’ve given this the name Agave ‘Supersize’. It has achieved a size of 6′ tall x 8′ wide in that time. To put this in perspective, it is larger at 6 years old than both parents were at 15 years old. If Agave ‘Supersize’ waits until age 15 to flower, it could easily reach more massive proportions that any Zone 7b winter hardy agave in existence.
We have been fascinated with hardy cyclamen since the 1960s, but in recent years have spent a bit of time isolating some of the best silver-leaf variants that showed up in our seed pots and getting these established in the garden. These silver leaf oddities can be found in the wild, although they are fairly rare. In cultivation, however, they come fairly true (50%) from seed.
Through Plant Delights, we offer these as seed strain cultivars, under the names below…when available. A new crop of cyclamen will go on-line January 1, and there are some real beauties. Here are some images from the garden this week. Winter hardiness is Zone 4a-8b.
While we leave all the fancy mangave creations to our friend Hans Hansen at Walters Gardens, we continue our work on creating more winter hardy (to 0 degrees F) hybrids. Over the last couple of years, we’ve made several crosses using some of Hans’ hardiest Agave ovatifolia based F1 generation selections, like xMangave ‘Blue Mammoth’ and xMangave ‘Falling Waters’ and crossing them back onto Agave ovatifolia.
The F1 mangave hybrids from Hans’ work, have all lost the monocarpic trait of pure agaves, meaning they will not die after flowering. We are curious what will happen if the hybrids have 2 parts agave and one part manfreda. With most of our crosses, we grow 100-200 of each into 1 qt pots, which allows us to do an initial culling after seeing the juvenile foliage traits.
The photos below are from that process, which happened this week. This is a cross of xMangave ‘Falling Waters’ x Agave ovatifolia ‘Frosty Blue’. The first image shows the diversity in the seedlings. All plants have some degree of glaucous foliage…some more toward blue and others with purple spotting that comes solely from the Manfreda parent. It was interesting that the F2 plants still showed some degree of purple spotting…probably around 5% of the plants.
From a batch of 100-200 plants, our goal is to select 10% for the next round of in ground trials. We focus on selecting at least one plant for each desirable trait. Those traits include: size (dwarf or large), leaf undulations, spotting density, best blue color, leaf twisting, leaf length, leaf width, overall form, best spination, and variegation.
Below are some of our final selections for the next phase of trials. These will be up-potted into 3 quart pots and overwintered indoors, since we’re already too late for planting outdoors this year. These will go into the ground in spring, after the danger of frost has passed.
I wish I could count how many times we’ve been told, “That won’t grow in your climate.”. Our contrarian streak has led us down many interesting paths, with quite a number of surprising results.
The most recent is Chrysophyllum oliviforme. Over a year ago, we planted seed grown plants, native to the recently hurricane-ravaged Sanibel Island, Florida. This species is native to Southern Florida, the Bahamas, the Greater Antilles, and Belize. With that distribution, it should have no chance in our winters, but, despite die back during last winter’s low of 16F, it returned, and is now approaching 4′ in height. I should add that our plant was planted on a very exposed site, with no protection.
Is it going to be a long-term plant….probably not, but there is obviously more winter hardiness than most informational sites would lead us to believe. I should add that we planted two seedling, and the other one planted nearby, succumbed to the winter temperatures. If you never take risks, you’ll rarely get to experience the joy of amazing surprises like these.
The genus rhodophiala is in a state of flux. Some taxonomists believe the genus actually doesn’t exist and should be merged with rain lilies, while others consider it a perfectly valid genus with 27 species. Oh, the joys of taxonomy. To most gardeners, the genus rhodophiala are simply dwarf hippeastrum (horticultural amaryllis), the most commonly grown of which is the South American Rhodophiala bifida, which ranges natively from Southern Brazil into adjacent Argentina.
Rhodophiala bifida starts flowering for us in mid-August, alongside the emerging foliage. Most Rhodophiala on the market are the clonal Rhodophiala bifida ‘Hill Country Red’, brought to the US by German born Texan botanist, Peter Henry Oberwetter circa 1890. This clone is virtually sterile when grown alone, but will produce viable seed when grown adjacent to another clone.
Below is the clone ‘Hill Country Red’, followed by some of our selected seedlings, all photographed here at JLBG over the last couple of weeks. The best conditions are full sun to light filtered shade, and average moisture to dry soil.
Rhodophiala bifida ‘Harry Hay’ seems to be the only named clonal selection grown in the UK. We imported this during our 2020 UK trip.
Rhodophiala bifida ‘Carmencita’ is our first named introduction, released in 2017.
Rhodophiala ‘Red Waves’ is our 2nd named selection, not yet introduced
The rest of the clones below are our selected seedlings still under evaluation
Below are two fascinating plants from our breeding. The first is a cross of Rhodophiala bifida x Lycoris longituba. In theory, this bi-generic cross shouldn’t work, but the flower arrangement sure resembles a lycoris more than a rhodophiala.
This cross is of Rhodophiala bifida x Sprekelia formosissima is another impossible bi-generic cross. Notice the three petals are one size, and the other three petals are larger. We’ve never heard of this happening in rhodophiala, so perhaps we’re on to something.
The only other Rhodophiala species, which we’ve had any luck with is the Chilean Rhodophiala chilense. Below are two forms, both of which flowered this spring.
I wonder if the late Atlanta nurseryman, W.L. Monroe had any idea what would become of his white-flowered monkey grass, that he selected as a seedling and subsequently introduced to the gardening world in 1957?
In the 65 years that’s passed since it’s introduction, Liriope muscari ‘Monroe White’ is still the gold standard by which all white-flowered liriope are judged. Here are our plants flowering this week at JLBG. Unlike most liriope, which thrive in sun, this cultivar needs light shade for most of the day to prevent foliar scorch. Our plants in the photo only get a couple of hours of direct sun, where they thrive. Winter hardiness is Zone 6a-10b.
We’ve long had an affinity for larches (probably due to a hangover from watching the Monty Python larch skit far too many times), but there aren’t many larches that will survive our hot, humid summers. We can, however, succeed with the false larch, which belongs to the monotypic genus, Pseudolarix. Both larix (larch) and pseuodlarix (false larch) are deciduous conifers, whose foliage turns golden yellow in fall prior to leaf fall.
Pseudolarix is known as an open, airy species, and having seen quite a few over the last 50 years, all were very similar. Imagine our surprise, when a new seedling we purchased in 2017 turned out to be incredibly dense and fast growing. The first photo is our oldest typical pseudolarix, now celebrating 29 years in the garden.
The new clone, which we’ve named Pseudolarix ‘Greensanity’, just 5 years in the garden, is pictured below that. We look forward to working with some woody plant nurseries to get this exceptional form grafted and into the trade.
This spring, one of our flats of Rohdea japonica seedlings turned up with an inordinate number of variegated seedlings. In a flat of approximately 1,000 seedlings, we typically expect 3 – 10 variegated offspring, when the parent plant has white streaking in the middle of the leaf (L2 layer).
All of the variegated seedlings were removed and potted individually last week…all 300 of them. It will be fascinating to see what unique forms result.