The Look of Love

If you’re able to visit during this years spring open house, it will be hard to miss the look of love in the air. We have a record 20 century plants in spike in the garden…a number far surpassing any flowering record we’ve set previously.

Agaves are a genus of mostly monocarpic plants…they live their entire lives to flower once, then after experiencing a giant-sized orgasm, they fall over dead. In the wild, many species take up to 100 years to flower, which is why the name century plant stuck as a common name. In our more rainy climate, our century plants typically flower in 12-15 years. Several of our current crop are actually less than a decade old, but their enormous size has already been achieved, so they’re ready to reproduce.

Some species of agaves offset, and in this case, only then central rosette dies, and the offsets continue as is the case with bromeliads. Those agave species which never offset are one-and-dones, but hopefully will leave behind a plethora of seed for the next generation. From the start of the spikes to full flower is usually about 8 weeks. Below are a few of our babies in spike.

Agave ovatifolia ‘Vanzie’
Agave x ovatispina ‘Blue Arrows’
Agave lophantha JLBG-01
Agave x loferox JLBG-014
Agave x pseudoferox JLBG-176

A Characias Cracker

For years, we struggled to grow the Mediterranean/Balkan native spurge, Euphorbia characias…until we discovered its secrets. First, it isn’t a long lived plant to begin with…in most cases 3-5 years is it, so you’ll need to plant it where it’s likely to reseed. That would be well-drained slopes that are either mulched or covered with gravel.

Secondly, after it flowers in spring with its stunning show of yellow flowers, remove most of the flower stalks as soon as flowering has finished, except those needed to produce new seedlings (the flowers are also great to use in floral arrangements). If not, the seed stalks use up energy causing the plant to decline much faster. We’ve now allowed this to seed throughout the slopes in front of our house, and here is the result…a smattering of 3′ tall x 3′ wide clumps, photo taken mid-winter.

Although this section of the garden, planted in compost-amended sandy loam is irrigated, we typically don’t recommend irrigation for this spurge without excellent drainage. You’ll also read on-line that Euphorbia characias doesn’t like hot, humid summers…another example of fake gardening news that just keeps getting repeated without any concern for the facts.

We’ve also found Euphorbia characias to grow well in part sun under large trees, which keeps the soil dry. The plants will never be as dense as they are in full sun, but they survive and flowers. There is really not anything else that gives you this evergreen blue color and form in the winter garden.

Are you a blue fan?

We love our Mediterranean blue fan palms…one of the coolest palms we can grow outdoors. We’re right on the edge of winter hardiness for Chamaerops humilis var. argentea, so the key is to grow it to a larger size before planting in the ground. We’ve lost a few that we planted too small, and when that planting coincided with a cold winter.

This is a photo taken this January of our oldest clump, now 17 years old. This is a very slow growing palm, so a good bit of patience is required when getting it established. When we do experience single digits F winter temperatures, all of the foliage is burned back, but it re-sprouts from the base in spring. Mediterranean blue fan palm hails from high elevations in the Atlas Mountains of Morocco, where it eventually makes a 15′ tall specimen. In our cold winter climate, we doubt it will ever top 4′ in height. It should be winter hardy from Zone 7b and warmer.

Mangave zombies

One of many great attributes of mangaves, compared to one of their parents, agaves, is that they don’t die after flowering. Agaves are mostly monocarpic, which mean that they behave like bromeliads, where each rosette grows to maturity, then dies after flowering. Those species of agave which offset, live on after flowering, by means of un-flowered offsets. Those agave species which don’t offset are a one and done after they flower and reproduce by reseeding.

By incorporating manfreda genes to create xMangaves, the monocarpic trait disappears. After a mangave flowers, it dies to the ground, but like a good zombie, it soon pops back from the dead. Here is a current photo from the garden of two clumps of xMangave ‘Blue Mammoth’. The first, larger clump has not flowered, but should do so next year. The second clump with all the offsets, flowered in 2020, and re-grew to this point in 2021. Next year, the rosettes will continue to re-grow in size.

We don’t need no stinking leaves!

We’ve been experimenting to see how many species of asclepias will survive in our climate, and one that has been quite fascinating is Asclepias subulata. This odd species from the southwest deserts of the US has evergreen glaucous stems, and not much in the way of leaves. It will be quite interesting to see what the butterfly larvae actually consume. It did flower for us this fall for the first time. This will be our first winter, so fingers crossed it can take our cold and wet temperatures. We sited this on a slope in one of our crevice gardens, so it wouldn’t drown in our summer rains.

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’

Are you a blue fan?

No, we’re not talking about your favorite football or basketball team, but the amazing blue Mediterranean fan palm. Here’s our oldest (16 year) specimen in our alpine rock garden this week. Chamaerops humilis is a Southern Europe native that’s marginally hardy in our region, but the blue form, know as var. cerifera (or var. argentea). is much more tolerant of our cold winters. If our winter temperatures drop into the single digits F, the foliage dies back to the ground, but quickly rebounds in spring.

Chamaerops humilis var. cerifera

Upside down in Dry Shade

At our home, we have a very wide overhang which never sees any moisture, so we were looking for plants that would stay low, ideally evergreen, and would tolerate seriously dry shade. The answer was Echeveria ‘Topsy Turvy’. These patches of the Northern Mexican succulent, with blue-green foliage, have absolutely thrived here. While they probably wouldn’t be happy in deep shade, they love this high canopy with good light, but no sun. These were planted in 2018. We’d rate these as Zone 7b/8a if kept dry in winter.

Blue Ice is Hot

One of our favorite blue-foliage conifers that thrives in the southeast heat and humidity is Cupressus arizonica var. glabra ‘Blue Ice’. This is a four year old planting of the Arizona native that’s already made a nice size specimen. Cupressus ‘Blue Ice’ is great to use for Christmas arrangements, due to it’s color, foliage fragrance, and ability to hold up very well after being cut.