Sex for the Centuries

Since we are limited in the number of hardy century plant species, our only option for more agave diversity in the garden is to create it by crossing existing hardy species together. Here are a few of our recent successes.

Agave x amourifolia is a Plant Delights/JLBG creation from a cross we made in 2016 that combined the genes of three century plants, Agave ovatifolia, Agave lophantha, and Agave x pseudoferox ‘Logan Calhoun’. Our size estimates were that the offspring would mature at 3′ tall x 5′ wide. Here is one of our garden specimens photographed this week, which has already reached 2′ tall x 3′ wide.

Agave x amourifolia

Below is Agave x ovox, a 2017 cross of the two giants, Agave ovatifolia and Agave x pseudoferox ‘Bellville’. We expect this to get huge…perhaps 5′ tall x 10′ wide.

Agave x ovox ‘Large Ox’

Below is Agave x protifolia is a 2016 Mike Papay cross of Agave x protamericana x Agave ovatifolia. We also expect this to get quite massive.

Agave x protifolia

Below is Agave x ovatispina ‘Blue Arrows’, a 2016 Mike Papay cross of Agave ovatifolia x Agave flexispina. We would have expected this to be a mature size, but it’s achieved this in only 5 years, so we think we’re seeing some serious hybrid vigor.

Agave x ovatispina ‘Blue Arrows’

Below is Agave x ocareginae, our 2016 cross of Agave ovatifolia x Agave victoriae-reginae. Most likely, this elegant small grower will never offset.

Agave x ocareginae

Below is Agave x schuphantha, a 2015 Mike Papay cross involving three century plant species, Agave schidigera, Agave lophantha, and Agave lechuguilla. It’s formed a beautiful, symmentrical rosette, which should be getting close to mature size.

Agave x schuphantha ‘Wheel of Fortune’

Vilmorin’s Oak

Outside of the nerdy members of the International Oak Society, few gardeners have ever heard of Quercus x vilmoriniana. This spectacular oak is a hybrid between the Asian Quercus dentata and the European Quercus petraea. Quercus x vilmoriniana has been known in European gardens since 1894, but is rarely seen in US gardens. The hybrid is named for the late French botanist Maurice Leveque de Vilmorin.

Our 20′ tall specimen at JLBG was planted in 2012 and has developed not only superb foliage, but splendid deeply-fissured bark. There is an old specimen at Cornell in NY, so it shows good cold tolerance in addition to loving our hot, sweaty summers. We have sown acorns from our plant, and if they grow, we will make this available though the Southeastern Plant Symposium Rare Plant Auction in June.

Sibling rivalry

As a plant breeder, one of the cool things we get to do is observe the diversity that arises from a single cross. In some cases, the diversity shows up in the first generation (F1), while in other cases, the first set of offspring need to have sex with each other for the diversity in the offspring to reveal itself (Mendelian genetics). Fortunately, with agaves, we can see quite a bit of diversity in the F1 populations.

Below is a cross we call Agave x amourifolia, which is our cross of Agave ovatifolia, pseudoferox (salmiana var. ferox of Hort.), and lophantha. Here are three of our selected seedlings from that cross.

Plant #1 below is showing the large size of Agave x pseudoferox and the color of Agave ovatifolia (blue), with little visible influence of the narrow leaf, yellow-centered Agave lophantha.

Agave x amourifolia

Plant #2 below show more color influence from Agave x pseudoferox, but with the compact form influence of Agave ovatifolia.

Agave x amourifolia

Plant #3 below shows equal parts Agave x pseudoferox and ovatifolia, but also, what appears some leaf narrowing we would expect from Agave lophantha.

Agave x amourifolia

Below is Agave x flexiferox, created from a cross of the small Agave flexispina x the giant pseudoferox (salmiana var. ferox (Hort.). Plant #1 shows the small size of Agave flexispina, with the greenish coloration of Agave x pseudoferox.

Agave x flexiferox

Below, Agave x flexiferox ‘Megalodon’ shows the larger size and overall coloration from Agave x pseudoferox, with some added blue tones from Agave flexispina.

Agave x flexiferox ‘Megalodon’

Below is Agave x victoferox, a cross of Agave victoriae-reginae x pseudoferox. Plant #1 below shows the form and size of Agave victoriae-reginae with the color of Agave x psedoferox.

Agave x victorferox

Hybrid #2 below shows the teeth from Agave x psedoferox (victoriae-reginae has no teeth), and a size intermediate between the two parents.

Agave x victorferox 2

Hybrid #3 below shows a larger size and more teeth due to more genes from Agave x pseudoferox. The teeth are much smaller because of the Agave victoriae-reginae genes. The splendid compact form also comes from the Agave x victoriae-reginae parent. This cross almost resembles the Northern Mexican Agave montana.

Agave x victorferox 3

We hope this gives you a small peek into the world of plant breeding and the subsequent evaluation and selection process.

Bletillas everywhere

Not only are bletillas one of the easiest ground orchids to grow in the garden or in containers, they are also one of the few that are easy to grow from seed. We’ve been growing seedlings for the last decade and having discarded several thousand plants (hint…they are all nice), we’ve narrowed them down to our final few selections, a few of which are pictured below. In addition to the differences in flower color, flower size, ploidy level, there are dramatic differences in flowering season and height.

Below is a Peter Zale hybrid, Bletilla ‘Candles in the Wind’, which Plant Delights will be introducing in spring. The floriferousness and height are the first two things you notice…there just aren’t many 4′ tall bletillas. In the eight years we’ve trial this, it has spread from a small plant to form a 6′ wide patch. This is a truly astonishing selection.

Bletilla x brigantes ‘Candles in the Wind’

New Notocactus

Several of our volunteers have dabbled with cactus breeding, so here is one of the hybrids we’re currently enjoying at JLBG, thanks to the creative efforts of Mike Papay. The top image is the female parent, Notocactus ottonis (yellow). The middle image is the male parent, Notocactus herteri var. roseoluteus (pink). The bottom image is the new hybrid, Notocactus x hertonis (peachy orange).

Notocactus ottonis
Notocactus herteri var. roseoluteus
Notocactus x hertonis

When is a May Apple no longer a May Apple?

Back in 2009, the since deceased Delaware Valley plantsman, Jim McClements, shared a may apple hybrid he’d created by crossing the US native Podophyllum peltatum with the Chinese native Podophyllum pleianthum. The offspring was named Podophyllum x inexpectum ‘Ruby Ruth’ (after his second wife). Our plant spent years in a much too dry a garden location until we relocated it to a bog setting alongside pitcher plants. Finally this year, we got our first flowers…a lovely bright red. Now the dilemma is that some Chinese researchers consider their may apple not to be a podophllum at all, but instead a sister genus, Dysosma. If we buy into that theory, then our plant becomes a bigeneric hybrid that will need a new nothogeneric name, either x Dysophyllum or x Podososma. After growing most of the growable species, I’m having a hard time supporting the idea of two separate genera, but we’ll see.

Sex in the Pulpit

After being told several years ago that creating interspecific hybrids of arisaema (Jack-in-the-Pulpit) was virtually impossible, we started our own breeding program. Here are a few of our creations from our Contrarian Frankestein Lab that are looking quite nice this week.

Arisaema x heterburgii ‘Black Snake’ (heterophyllum x thunbergii)
Arisaema x heteroguineum ‘Pirate Sail’ (heterophyllum x consanguineum)
Arisaema x trigesii ‘Neptune’ (triphyllum x fargesii)