I planted a very poorly rooted yucca carnerosana in my arid bed a couple of years ago bed but unfortunately as you can see it grew no new roots at all and slowly faded.
However I potted on a similarly poorly rooted yucca rostrata at the same time. I replaced the carnerosana with the rostrata yesterday and it had developed a fabulous root system. Here it is in place.
I also lost a few agaves this winter and have replaced these with a few common plants until I decide what to plant in replacement.
I quite like the libertia ixiodes or New Zealand Iris, not sure how easy it is to grow? The small green succulent is delosperma nubigenum.
Finally, I decided not to protect my brahea armata at all this winter and its come through without a mark on last years growth.
I grew both the normal libertia ixiodes and the goldfinger variety in my dry bed without any problems at all. I gave mine a bit more soil around the plant and gave them more water during very dry spells.
Is the yucca in the front a banana split or bright star. This is my bright star.
I am less fussed by my banana split, but Melissa has hers planted and it looks great.
If you don't already have one then agave bracteosa should work well.
I have also enjoyed collecting the largest sempervivums I can find.
OK, here's a comprehensive Yucca report. In response to the death of numerous experimental species of Agave on the green roof, after the Winters of 2009/10 and 2010/11, I decided to replace their visual accents with numerous experimental species of Yucca.
I'll pass briefly by my two mature, even elderly Y. gloriosa variegata, which have lived in the ground since 2000, when they were already no longer young. They have both flowered in the past 2-3 years and have split into 2 and 3 heads respectively. They're in the post-flowering untidy phase.
I've had a chunky, 500mm tall, multi-headed Y. aloifolia from Amulree sitting in its pot since one of last year's sales, because its root-ball is just too big/deep/heavy to plant on the roof. Just yesterday, I came up with a spot in the ground where it might get enough sun and I'll plant it there when I have the energy. There is also a small seedling Y. aloifolia that I obtained from Jan Matiaska in Slovakia. It has been planted out on the roof for several years and is growing v-e-r-y slowly, but steadily.
I tried out two Y. faxoniana on the roof last year and have retained one in its pot. Both on the roof have been unscathed by last Winter, but they aren't too pleased with life in 100-200mm deep soil and they all have some kind of fungal leaf-spot (as has one of the Y. gloriosa variegata). They're smaller now than they were when I bought them. The third one will remain in a pot until I work out what to do with it.
Similarly, I planted out two Y. gloriosa (the real thing) on the roof last Spring. They are slightly chlorotic (I fertilised them very sparingly last month - generally, I never fertilise the roof), but they are growing and they look OK.
I planted out three of the profoundly hardy Y. glauca on the roof last year. They're all alive. One is doing well. The other two have dried-out growing points and I'm waiting to see what they do next.
I bought two of the enviable and cherished Y. queretaroensis (a magnificent plant that I have seen at large scale in Mexico - mine are about 250mm tall) last year and left them, unprotected, in their pots on the roof. They're fine. I planted out one up there yesterday.
I planted out several cuttings from my enormous Y. elephantipes on the roof last Summer. Most of them are failing, but one or two look OK and are growing. The big one in the ground is looking unhappy - I think a couple of trunks have some kind of internal decay and it may need cutting back soon.
I doubt that any of these species will achieve their full grandiosity in 100-200mm depth of low-fertility soil in a cool-summer climate, but if they survive and grow, they'll look good and in scale with what is around them.
Chris wrote:Is the yucca in the front a banana split or bright star.
It's Banana Split Chris. To be honest not my favourite Yucca, a bit straggly and snails love it. I keep it very well 'clipped' to avoid hiding places for the little blighters. Do you have a picture of Melissas?
David wrote:OK, here's a comprehensive Yucca report.
Good report David, a few comments.
I have a multi trunked Yucca Aloifolia growing under the shadow of a large crab apple tree and it's doing surprisingly well. All the literature says they need perfect drainage - mine is in heavy clay.
I have Yucca Gloriosa (to the left of the Rostrata in the second photo above) and they can look surprisingly effective until they flower and get in a right old mess. Mine is also susceptible to black spotting.
As you say it is unlikely any of the larger Yuccas will grow to any size on your roof but they will probably survive in what is a relatively hostile environment. Do you grow any of the smaller species, like Bright Star or Banana split mentioned above, or even a small Rostrata should do well. I've also got aloifolia Purpurea?? which has again survived the winter and is trunking nicely.
Steve, I don't have a photo of mels banana split, she does look in here every nw and then so hopefully she will have time to pop a photo up. She also has countless yuccas so may be able to give a report on which ones have done well for her.
So far I have two large rostratas which never get troubled by the winters. Then a bright star and a smaller banana split. i still think Bright Star is better, it seems faster and better colour and even in a pot coped better with winter. Mind you I think to do well they both need to be in the ground. Then a Yucca Gloriosa Variegata which you see everywhere around here. I also had a yucca Baccata which was a tiny plant but never got troubled at all and small yucca whipplei which again didn't have problems, apart from snow weighing it down close snapping. (DM that may be another one for you).
I also have the Purpurea which I think people are suggesting may be a desmettiana hybrid. not left this one out yet.
I got a couple more n a recent trip to see Mel, although can't remember which ones. I am also thinking of getting a couple more of the stiff leaved ones which are missing from my collection.
Steve.... Thanks for your update. Its good to see the Rostratas in good condition, testament to a good root system. The Gloriosa is stunning very upright like the form "Nobilis"
Yucca carnerosana is similar to Faxoniana but less hardy. Trunked yuccas have on average a 40% chance of surviving compared with seed grown plants at 80%.
I completely roofed my main Arid border this Winter to give the plants a chance to bed in and root. All my Yuccas including Thompsoniana, Faxoniana, Queretaroensis, Rostrata , Linearifolia X 3, Rigida. I have four Nolina species... young plants, all came through undamaged.
I have just acquired a large 7ft Rostrata, a huge fat trunked Treculeana and a trunked Elata which I have to plant soon (somehow)
Additionally I have planted another Linearifolia and a Rostrata recently after replacing several tonnes of soil
Failures.... well both Yucca Aloifolia and variegate suffered rain damage on leaves and an unprotected green Rostrata looks a bit washed out but the damn plant flowered one month after planting it out last spring
Under the roofed area I lost Agave Gentryii and also had damage to a Butia Odorata which has baffled me somewhat.
Find of the Century was a 25year old Nolina Nelsonii.
Sorry no pics as my pics are too big which is weird as most forums automatically adjust now??
The general sentiment seems to be that what is sold as Y. aloifolia purpurea is probably a cv. of Y. desmetiana. I forgot that one, for some reason. I planted three on the roof. One lasted a year and expired. Another is looking unhappy. The third is still growing. So we'll see.
Rostrata has rotted off due to a poor root system - will get a linearfolia next time. Large aloifolias have both grown well in the last year, only reason can be lots of summer rain. Gloriosa Variegata, recurvifolia and filamentosa are all suffering from the spotting problem which from what I can see on my travels seem to be afflicting the wide leaved species. I have been spraying with rose clear for a couple of years but the problem is getting worse.
