At PDN there are multiple new raised succulent beds (along the parking lot) - we've seen PDN solicit on Craigslist deliveries of broken concrete to build them.

They are still in early stages of growth, looking rather eclectic with mulched areas containing xeric perennials and graveled areas with bona fide succulents:

At their bookends they have "crevice beds" with tightly packed chunks of concrete:



While we are very enthusiastic ourselves about using broken concrete for the internal bulk of raised beds, we are more skeptical about the esthetic qualities of leaving exposed concrete in the crevice sections - that in our opinion still calls for natural rock slabs.

I usually forget to mention them because they’re just so dang reliable, but my Orostachys didn’t skip a beat after last winter in their pots outdoors, and it’s shaping up to be a stellar bloom season.

We overlooked the robust cluster of Agave lophantha (species) in X04, because the plants are much larger and leaner than what we have in pots:

That corner of the Xeric garden is quite shaded, which would explain the elongated leaves. There seems to be some debris of damaged lower leaves, but the plants are in great shape overall.

Here's a current picture of the whole Agave ovatifolia 'Frosty Blue':

There is a very nice hardy succulent bed in the Bartholdi Park in Washington, DC at the corner of First and Independence. Here are some pictures from the end of September.

Its centerpiece is a large Agave americana:

and apparently planted out long enough to start offsetting:

A. americana is mostly rated Zone 8a, sometimes even 8b so it is interesting to see no signs of damage. (Washington, DC is often considered Zone 8a, due to the effect of urban heat island). And it is not labeled as the hardier variety 'protoamericana' rated down to 7b (sold also by PDN).

The bulk of the bed is planted with various zone-pushing succulents - some of them Zone 8a and lower, for instance Dyckia 'Burgundy Ice':

(this BTW is quite a nice black plant - Karen W, do you have it?)

Helichrysum 'Icicles':

but a few not lower than Zone 9, for instance Graptopetalum paraguayense:

and various Kalanchoes, Echeverias, here Kalanchoe marnieriana:

Echeveria gibbiflora:

so we suspect that some of them may be replanted as annuals - it would be very interesting to find out if some of them are really hardy.

Les, I don't have 'Burgandy Ice' - looks interesting, especially if it winters over in D.C. Would be nice to see photos of that same planting in February. The really dark foliage Dyckia that I'm looking for, though, is Dyckia 'White Fang'.

'Mack the Knife' is pretty remarkable too, better teeth though not quite as black.

White Fang

Mack the Knife

A number of sources list Dyckia 'Burgundy Ice' as Zone 7a (including the rather reliable Annie's Annuals), although some still say Zone 9. But for D. 'Grape Jelly' most say Zone 8a.

(Please note that your image links throw a "403: Forbidden" error).

Les, edited the links. They work for me now.

Speaking about Echeverias, we were amazed to see E. runyonii (both the species and the 'Topsy Turvy' variety) growing outside in Vlad's garden - as it is listed Zone 9 by so many sources. But now we see that PDN has it as Zone 7b. So the hardiness of many succulents needs to be explored empirically without blindly copying the zone of the native location.

Here's a task for Echeveria experts: identify these two plants:

Karen, edited links still don't work as is. They do though if we modify them by changing to www.fcbs.org.

Thanks for that Les, they had quit working for me too so I edited to add the www to the url. Will check again later to see if they still work.

OK, this is nuts. They both worked, then the second one became forbidden again. I think it would be quicker to order plants and take photos myself. How's that for rationalizing a plant purchase?

Looks like erratic behavior of their Web server. Both seem to work more consistently if explicitly preceded by "http:/". This way "www" is not needed any more.

I found some different websites for the photos and linked those. But the fcbs.org site is one of my favorites for looking these up, despite it's erratic behavior today. If the links don't work now, will have to conclude that it's me.

Nice pictures Les.

That agave Americana in DC ... NO WAY!!!! Not with the amount of moisture and cold they have. It must by a hybrid. Possibly Americana and Salmiana ... Even my "the hardiest Salmiana" (marked by Tony) did not make it outside. But I keep trying.

Vlad

We are happy to have received another batch of broken concrete (thanks to Sarah from Durham) and performed another expansion at one of our two locations of the raised succulent beds - this is already Phase IV since they were started in March 2016.

We actually ran out of material for what was the intended expansion at this stage - even with an extra wheelbarrow of leftovers from a previous deployment, this bed is still not complete. So we are still looking forward to getting more concrete.

Looks really good Les

Vlad

After adding a rock front retaining wall (riprap B from TLS) and several plantings, still raw:

Among the plantings: Agave victoriae-reginae (right center) and Opuntia 'Baby Rita' (right back) from Vlad.

A very interesting report about how cold damage to Agave ovatifolia, normally a non-offsetting species, induced multiple growing buds (multiheaded form) that could be separated after recovery. In German, but pictures and dates self-explanatory. The title of the post: "The Legend of the 9-headed Hydra".

During expansion of our south west raised bed, we discovered that the area is extensively flooded after rain - it is in a lower section of our sloped property and two runoff currents seem to meet in that location:

Now we understand why several plants with dry soil preference died in this location in spite of its very sunny and hot southwestern exposure: Cynara cardunculus, Kniphofia, and Yucca rostrata.

So we dug it much deeper than usual - about 18 inches instead of 8-10 - to provide more room for the water to sit at the bottom:

Since this is pure clay, the drainage is extremely slow - so the worst case scenario is that the hole will fill up fully and the water will start flowing over the edge.

After this, it was business as usual filling the hole with broken concrete and adding a drain pipe that empties above ground:

And finally building up the raised part:

And adding a front retaining wall using rock (riprap B):

There may be more moisture in this section of the raised bed due to capillary effects, so it may be less than ideal for something extremely sensitive, but the bulk of concrete above the maximum water level should make it acceptable for other succulents.

Woow Les ... a lot of work. Good stuff!

Vlad

Senor Vlad gave us recently an Agave difformis (yes, difformis means deformed) and the first thing that struck us is its similarity to Agave lophantha. Indeed, PDN says that it "is a relative of the easy-to-grow Agave lophantha and Agave lechuguilla [...] makes a 18" tall x 2' wide freely suckering clump composed of wavy, medusa-like upright green leaves, often highlighted by a wide central silver stripe". They rate it only to Zone 8a.

Below is an illustration of the variability of A. lophantha-like forms - left to right: A. difformis, long-leaved A. lophantha (grown also at JCRA), compact A. lophantha (all from Vlad):

Interestingly, variegated forms of A. lophantha, such as 'Quadricolor' and 'La Bufa Baby', seem to grow only in the compact, not long-leaved, shape.

... And I have not tried any of those outside. I had the quadricolor outside and the mother plant died the penultimate winter. The pups have survived and passed one winter. We will see how they do next winter.

Vlad, you made me get my dictionary out!

The Echeveria experts have wisely taken a vow of silence regarding the ID challenge posted above on November 26, 2018, as it was a setup. The plant on the right is not Echeveria at all, but Sedum spathulifolium. The one on the left is the cold hardy Echeveria from Vlad.

We were driving on our home street this week and five houses down the road a neighbor was removing their driveway - what a joyful sight! It looks like this Fourth of July we'll be declaring independence of having to beg strangers on Craiglist for broken concrete. We have obtained from the neighbor enough material to fill the gaps of the still unfinished SW bed and to put a few wheelbarrows as reserves for smaller future projects into the crawl space:

Vlad used a drone to make a great video of aerial views of PDN including, but not limited to, their crevice beds.

Les, these are Orostachys as grown at Montrose, in a large metal kettle/pot.

Our Agave lophantha species, planted out in April, has done very well during the summer heat and drought but puzzlingly has suffered a lot of damage that began in October and got worse recently:

We also noticed that some potted A. lophanthas developed minor blemishes on their lower leaves during the heat, but that subsided after they were moved to some shade.

In contrast, A. lophantha 'Quadricolor', two feet away, perfectly unblemished and growing already two pups (one behind it, not visible):

Very nice Les. My A lopantha quadricolor survived in a pot!!!! the latest 24-25 degrees. We will see how cold we can get...

Just when we thought that we knew all the major invasive plants (Wisteria sinensis, Pueraria sp., Lonicera japonica), we have to add one more to that list: Agave lophantha 'Quadricolor'. It is really exploding in our outside bed with long range offsets:

A larger cluster in the back:

Interestingly, the front offset (left side of the mother) in the November 26, 2019 at 6:47PM picture died off in the winter in spite of the mild weather (only limited browning of lower leaves on the mother plant observed, pictured in March):

Les, the length of those runners is impressive. Makes me both want and not want to try this.

While the problem of invasive succulents is not something that would keep us awake at night, we are not too eager to re-enact Vlad's wrestling matches with his infamous Mr. Ripple.

Anyhow, there will definitely be some more 'Quadricolor' pups at the next swap, whenever it is going to happen.

I think we need a video of the Vlad vs Mr Ripple match up.

I CAN provide that :-). Probably this fall I will shoot one. But yes, the wrestling matches are ... epic!

Vlad

Here are a few pictures from previous years:

https://photos.app.goo.gl/iuQpQF2ZF45YamgB6

https://photos.app.goo.gl/JqBRUA9Yu4Br39KG9

There was a video of Vlad after some kind of gardening struggle, most likely with Mr. Ripple, all disheveled and with swollen rashes, essentially saying "you should see the other guy". Is it still available?

Edited after the above links showed up: that picture was definitely part of the story, not sure now if there was a video as well.

Our A. lophantha species has recovered very well from last fall's mysterious affliction (pictured above in the November post) but is offsetting much less than 'Quadricolor' - only one minor offset so far:

We took out one of the 'Quadricolor' offsets that had wandered so far away from the mother plant that it ended up outside the raised bed on the path (the one closest to the bottom of the picture) - and it is shedding light on their spreading ability. Not that there is a huge root mass there with budding offsets - the plant just forms long wandering rhizomes, like a bamboo:

In the spring of 2020, we finally got to building two "crevice bed" extensions on top of our otherwise already raised concrete beds. They are supposed to be particularly well drained environments and in one case, we included an extra feature to make it super-well drained. For this crevice mound, we filled the bulk of the crevices with styrofoam peanuts:

And covered them with sand and lava rocks:

And crushed rock filling:

The first planted (still in the spring of 2020) test cacti were Echinocereus from J.L. Hudson seed mix:

And one of the seedlings of uncertain identity we received from Vlad, which he thought might be Escobaria vivipara:

They appeared stable through summer and fall and shrank slightly by early December in anticipation of winter (a good sign):

Unfortunately, only the Echinocereus survived the winter:

while the "Escobaria" lost its firmness and died (both pictured in April 2021):

We'll continue adding more succulents to this crevice mound - it could be very suitable for Orostachys, which we lost planted in the regular raised concrete.

The second of our crevice mounds was shorter and filled only with PermaTill, with two different Echinocereus forms planted in the spring of 2020:

And both of them not only survived the winter, but one of them actually bloomed:

(pictured April 27 and May 22, 2021, respectively).

Actually the "Escobaria" I think it was a mammillaria Grahamii. They do say it is hardy to 8a...

Mammillaria grahamii makes sense - in particular those fishhook whiskers that make it stick to everything like Velcro and give it its common name. However, the last winter here was definitely 8b, so it does not seem suitable for our area outside.

Ironically, though, it doesn't seem to like a warm winter, either. We've lost a few of them that were kept in the house, and have now only one surviving (about 1 inch tall now) - it was kept outside except on the coldest nights.

After twelve years in the area, we finally went on our first visit to Duke Gardens (we needed to figure out the parking situation there). Several very interesting succulent sightings.

The largest barrel cactus we've seen in the area (6-8" diameter), Echinocactus texensis, plus an unlabeled dark-leaved Dyckia*:

Ferocactus wislizenii on the label, but its spines appear straight, not fishhooks - closer to the ground:

Opuntia microdasys, often listed as hardy only to Zone 9a, apparently doing very well:

Dyckia 'Silver Nickel':

* unfortunately, our own Dyckia 'Grape Jelly', obtained from Karen W. wasn't happy after an upgrade to a larger pot and died.

I'll be interested to see if that Dyckia at Duke Gardens is winter hardy. Was there anything on the labeling to indicate how long it's been planted there? And sorry to hear about the Grape Jelly. When did you repot it?

Nothing on the labels, but the beds appeared to be long-established and the plants show lots of offsets. But the issue is still whether they are hardy to the recent milder winters not dropping below 20 F or to the more typical Zone 7b temperatures that should be expected to occur in the area. We'll be watching that bed this winter. Unlike JCRA, Duke Gardens doesn't have an online catalog with planting dates, but they provide an extensive list of contacts under https://gardens.duke.edu/contact and their Collections Manager could be asked for more details, including the identify of the dark Dyckia.

We upgraded 'Grape Jelly' to a 4" clay pot in September 2020 but it was still small so we placed some organic spacer material at the bottom (sweetgum balls), which many succulents like, but the Dyckia clearly didn't extend its roots into that layer and started to suffer. We attempted to correct this, but it was too late.

On the other hand, Aechmea 'Prieto' finally took off after being put into more organic soil with Probase chips versus pure sandy/rocky cactus soil and has now one sizable offset.

Also, because of the pandemic and general challenges of bringing people in for an event we suggested to Vlad starting with a Zoom tour of our garden and we thought that you might be interested to join us as well.

Dyckia tolerate periods of drought but they're not actually succulents. In habitat they get a lot of rain during active growth, and I typically pot mine more like a Cryptanthus with a well drained mix but more organic matter than you'd use in a succulent mix. I also do my repotting in spring and summer. I try not to push that too late in the season so they have plenty of time to acclimate to the new pot before entering dormancy. You might also try a plastic or glazed pot next time to keep it from drying out as fast.

Most Aechmea are epiphytes, so your new potting mix sounds better. If we were in south FL we could stick 'Prieto' up in a tree and it would be totally happy hanging down from there.

I'd totally be up for Zoom touring your garden.

Two very interesting developments have taken place recently that shed new light on a cold hardy succulent discussed in this thread earlier. We are referring to the posts starting with "Speaking about Echeverias" and "The Echeveria experts" three and two years ago (Houzz doesn't do exact time stamps any more). The plant pictured there on the right, while looking very similar to Echeverias, was honestly believed to be Sedum spathulifolium, as it was obtained under such label.

The first development was that the plant flowered for the first time and the flowers don't look like Sedum's at all:

(Karen W. knows very well what they look like).

The second development was that the crevice garden at JCRA has an identical abundantly growing plant in their rooftop crevice garden.

This plant is labeled Orostachys furusei, which indeed appears to be the correct identification. It is definitely the most vigorous of all the Orostachys in that crevice mound, compared for instance to a very sparse O. fimbriata:

The good news from this confusion is that, believing that the plant was a Sedum, we planted it in a number of locations without regard to the potential moisture sensitivity that killed our previous Orostachys and it is doing very well in all of them.

Taken together these observations indicate that O. furusei may be the best adapted Orostachys for our area.

This from my O fimbriata in bloom last month. All flopped over on each other.

There is always the East Coast native, Opuntia humifusa. Yes, it does have those prickles but I still propagate them all over, included on containerized plants. And these guys could care less about cold and WET eastern winters.

Update on the Duke Gardens succulents.

Not sure whether their people read this thread, but after our constructive criticism about the unlabeled dark Dyckia, a tag appeared and it is indeed 'Grape Jelly':

No change of the appearance of the plant since the original picture from November (the closeup above shows only lower leaves, but the rest has no damage spots).

The long suffering Ferocactus wislizeni has suffered even more through the winter and shows more browning, but seems otherwise viable:

Echinocactus texensis is very robust though and has not changed at all (not shown) since the picture in the post below was taken in November.