delosperma & aizoaceae

[iann]

Only a very few of these interesting plants are easy to find in general horticulture, but literally hundreds of them are available from succulent specialists.  Many Delospermas are very cold hardy but some have thickened roots and are touchy about winter wet.  Most of the other shrubby Aizoaceae like Lampranthus, Ruschia, Drosanthemum, and Ocularia are only marginally hardy in the UK but thrive in coastal areas or with just a little protection.  Look out for "Drosanthemum hispidum" which is a mis-named Delosperma that is very hardy and tolerant of winter wet.  If anyone is interested I can provide some sources, mostly for seeds.

There are a few really choice alpine Aizoaceae, I know that some people here have some of them.  Delosperma sphalmanthoides, Ectotropis (aka Delosperma) alpina, and Neohenricia sibbettii.

[Lori S.]

Where do you garden, iann?  (It is not indicated in your personal info.)  Do you grow any outdoors year-round in whatever the natural conditions are in your area?  (I.e. Not in pots, not under winter-cover or in alpine house... ?)

[iann]

I've edited in a little more info to my profile.  I'm near Manchester, fairly wet, cool summers, but not too cold in winter.  I have a number of Delospermas in the garden as well as some other mesembs.  Up against the south wall of my house, a lot of things survive in a very dry stony bed.  Elsewhere it is mostly just Delospermas, but I keep trying.  Some more Lampranthus and similar plants are offered up for sacrifice again this winter.

Here's a new species, or possibly a newly discovered old species, that I'm hoping will take to the garden because it has some of the nicest flowers on a Delosperma.  Its lovely in a pot but already has a taproot a foot long and wants to expand more.  Delosperma deilanthoides (possibly = D. galpinii).

[angie]

Hi Ian
Really nice Delospermas I have a couple but not with so many flowers as you have on yours, I always have had mine in pots and then I put them in the polytunnel just to keep the rain off them, but maybe I will try one out this winter and see how it goes.
Angie

[Darren]

Hi Ian,

Nice to see you on here as well as the BCSS forum!

[cohan]

great looking plants, ian..
when you refer to seed sources, do you mean the usual c+s seed sources (mesa, koehres etc) or some others with field collected or focussed on alpine/hardy species?

[iann]

Yes, mostly the sort of places you already know.  Places like High Country Gardens have a variety of Delosperma plants as well as other cold hardy succulents, but you might not be able to import plants to Canada.

Another useful specialist seed source is the Mesemb Study Group which issues a seedlist each year.  Its not really focussed on Delospermas though, but at least they will usually have the right name.  Delospermas in cultivation are more likely to have the wrong name on the label than the right one.

[cohan]

Delospermas in cultivation are more likely to have the wrong name on the label than the right one.

i got two locally this summer--i dont have the names in front of me now, but one had a cultivar name, the other a species name--i think my impression was that they should be nubigenum and congestum; i didnt think there seemed to be much difference, but i thought subtle differences are ok too..well, after growing side by side in my conditions all summer (still in pots, which are now sunk in the ground for winter) i'm quite sure they are the same thing....lol..oh well.... if they are still alive in spring, i will see what they look like...

[iann]

D. congestum is one of the abused names, usually applied to small mat-forming plants with yellow flowers.  D. congestum as originally described is an upright shrublet with white flowers and is not known in cultivation.

D. nubigenum is a mat-forming species with yellow flowers, often sold as D. congestum or with a cultivar name like 'Gold Nugget'.  Sometimes it has a white eye and it is likely that these plants have a hybrid origin.  There is also now a 'White Nugget', again an unknown hybrid.  There is no other Delosperma that you'd mistake for it, smooth rounded yellow-green leaves forming a mat no more than an inch high.

This same plant is also sold as D. basuticum, again a completely different species.  The name D. basuticum is also applied to a similar mat-forming plant with yellow flowers, but having sharper leaves minutely toothed along the edges.  I'm pretty sure this is also incorrect since D. basuticum is described as a having pink flowers.

D. nubigenum is extremely cold hardy and very tolerant of moisture.  Mine survive the weather but not the slugs!

[cohan]

D. congestum is one of the abused names, usually applied to small mat-forming plants with yellow flowers.  D. congestum as originally described is an upright shrublet with white flowers and is not known in cultivation.

D. nubigenum is a mat-forming species with yellow flowers, often sold as D. congestum or with a cultivar name like 'Gold Nugget'.  Sometimes it has a white eye and it is likely that these plants have a hybrid origin.  There is also now a 'White Nugget', again an unknown hybrid.  There is no other Delosperma that you'd mistake for it, smooth rounded yellow-green leaves forming a mat no more than an inch high.

This same plant is also sold as D. basuticum, again a completely different species.  The name D. basuticum is also applied to a similar mat-forming plant with yellow flowers, but having sharper leaves minutely toothed along the edges.  I'm pretty sure this is also incorrect since D. basuticum is described as a having pink flowers.

D. nubigenum is extremely cold hardy and very tolerant of moisture.  Mine survive the weather but not the slugs!

good to know! the one i got was labelled 'gold nugget'  a name which i tracked to congestum, so now i know that's wrong!  the other was labelled nubigenum, which was why i thought/hoped they'd be different; here are a couple of pics taken soon after i got them this spring, including a flower from the 'gold nugget', the 'nubigenum' did not flower yet;
 i seem not to have taken pics of both at the end of the year, but i'm quite sure they look the same as each other now; the loose/long leafed look of the nubi was no doubt due to nursery conditions..

[mark smyth]

I love these plants but flowering can be infrequent in my garden

[Lori S.]

Very interesting about the species confusion, Iann.

Bolus' original description of D. congestum (in latin) is shown in the attached link within a discussion about the frequently-confused species; the flowers are white, turning lemon-yellow ("alba, marcescentia citrina") as they persist:
http://www.fgas-sukkulenten.de/downloads/delosperma_e.htm

I couldn't find Bolus' description of D. nubigenum basuticum but here's an extremely terse description of it from the South African National Biodiversity Institute (SANBI) -  it does note pink petals.  (The other specimen described under the same species heading was not in flower but the leaves are said to match Bolus' description.)
http://sibis.sanbi.org/faces/SearchSpecimen/SpecimenDetails.jsp?1=1

(Amazing what one can find on the internet!  

[cohan]

Very interesting about the species confusion, Iann.

Bolus' original description of D. congestum (in latin) is shown in the attached link within a discussion about the frequently-confused species; the flowers are white, turning lemon-yellow ("alba, marcescentia citrina") as they persist:
http://www.fgas-sukkulenten.de/downloads/delosperma_e.htm

I couldn't find Bolus' description of D. nubigenum but here's an extremely terse description of it from the South African National Biodiversity Institute (SANBI) -  it does note pink petals.  (The other specimen described under the same species heading was not in flower but the leaves are said to match Bolus' description.)
http://sibis.sanbi.org/faces/SearchSpecimen/SpecimenDetails.jsp?1=1

(Amazing what one can find on the internet!  

well, that seems to muddy things even further! if congestum has white flowers and nubigenum pink--what are all these little yellow flowering things sold under one name or the other? although the first link you sent includes nubigenum in yellow flowering species...

[iann]

Wow, that was clunky!  I couldn't find that reference to a D. nubigenum with pink petals at SANBI and I don't think its possible to link directly into particular search results.  Possibly it was referring to the specimen as being unusual.  I'm sure a D. nubigenum with pink flowers would be a big hit in cultivation.  In any case, D. nubigenum is well documented with yellow flowers: "c. 30 bright yellow longer petals, c. 20 shorter ones, c. 10 deep yellow threadlike filamentous staminodes, around the c. 70 stamens".  Good flowering seems to depend on getting a good flush of early spring growth which is difficult in the UK.  I speculate that too much water early in the year may also suppress the flowers.

The name D. congestum is used extensively but is clearly wrong and clearly documented as wrong.  The original type is not known and the latin description has caused confusion, but clearly it never referred to D. nubigenum.  It may not refer to anything, many of the early descriptions were made from dessicated dead specimens, although Bolus tended to have better material.

Other yellow Delospermas common in cultivation, and there aren't very many, are D. echinatum and D. rogersii, both distinctive and hairy, and D. crassum which is a fairly standard sub-shrub Delosperma.  There is an unnamed tufted species from Lesotho which has almost inevitably been sold as D. congestum.  I show one in my garden, clearly different from any named species.  It is very hardy but the thickened rootstock seems a little sensitive to winter wet.  Anything else with yellow flowers is likely D. nubigenum or some hybrid of it.

[Lori S.]

No, no, sorry - a typo.  That was D. basuticum for which SANBI lists a reference with pink petals (corrected above) - it agrees with what Iann originally said.
(I don't think it actually works to post the SANBI search result - you may actually have to start from scratch in the search: http://sibis.sanbi.org/faces/SearchSpecimen/SpecimenDetails.jsp?1=1)