Delosperma update: The field narrows

Back in May, I posted about my experiments with trying to kill delospermas. I planted out entire collection out during the summer of 2012, in our native sandy soil, but no special conditions like raised beds or anything else. My goal was to see what THRIVES here in Michigan with no extra effort, so I just plopped two plant of each variety in the ground and waited to see what happened.

In May, I reported that 11 species had come through the winter just fine -- over half of what I had planted out to begin with. Which was more than I expected. I was surprised to find that over the summer many more bit the dust. We're now down to just 5. We had a summer that was slightly on the rainy and cool side, but nothing extreme. I never would have guessed it would kill so many delospermas. But it has, leaving me with a narrowing field of the very best delospermas for the Michigan garden. Here are the survivors, with pictures of what they look like today, with my comments:

Delosperma 'Firespinner'

This CLEARLY wins the vigor contest. This was a little, MAYBE 2 inch across plant just one year ago, and now the patch has spread to nearly two feet across. Way to large and aggressive for a rock garden or other small garden, but if you want a vigorous tough ground covering delosperma, this is the one I'd recommend. The flowers are stunning red-orange bicolor. (Sorry, we don't have this listed in the catalog yet, but should have some ready for sale by spring. If not, you shouldn't have trouble finding it for sale... everyone is growing this beauty.)

Delosperma ecklonis v. latifolia

Coming in a close second on the vigor department, this one has gone from two inches to a foot and half in just one year. Typical bright magenta flowers, heavy blooming in the early summer, with quite decent rebloom. As you can see, it hasn't quite given up flowering now, in NOVEMBER, despite quite a dose of freezing weather.

Delosperma deleeuwiae (possibly actually D. neill)

Delosperma 'Broncoensis'

Delosperma 'Lesotho Pink'

Not much practical difference between these three... all spread from their original ~2 inches to 6 or 8 inches, intense magenta flowers. Most of the plants in the garden suffered some die back in the centers of the clump, which gives them a bit of a patchy look. 'Broncoensis' is probably the best looking plant of the bunch (Note: we don't have this in the catalog at the moment. Stand by, we should have some ready to list soon.) and better for a small space than 'Firespinner' or D. ecklonis.

Delosperma nubigenum (this name may be incorrect...)

This is one of my favorites. The plant stayed quite small and tight, barely getting to 4 inches from the original 2 inch plant, which means this would be terrific in a rock garden or container garden. Yellow flowers, which is always a nice change from the typical delosperma magenta, and the foliage is taking on this lovely red flush as we're getting into fall. Apparently turning red in the fall is normal for most delospermas in sunnier climes like Denver, but here, where fall is cloudy and rainy, it is the only one really worth looking at.

Report from the trial beds: Erodium!

Erodium is one of those genera that I had vaguely heard of but didn't really know anything about before I started working at Arrowhead. They're closely related to Pelargoniums, and I'd always sort of assumed they wouldn't be very winter hardy. But they're proved me wrong on the hardiness front, and now, the more I see of them, the more I like them. The ones we grow all bloom continuously starting now in late spring and continuing on without a pause well into the fall. The flowering is never super heavy – these aren't plants that smother themselves with flower – but that is more than compensated for (at least in my mind) by the intricate beauty of the flowers and the absolutely terrific ferny foliage. Also a huge plus, so far the deer and rabbits haven't shown any interest in them (though I'm making no guarantees... if your critters are hungry enough they'll eat almost anything) and they absolutely laugh at drought, heat AND our cold, cold winters.

Erodium chelianthifolium

Erodium glandulosum

Erodium glandulosum and E. chelianthifolium are two of my favorites, and I'm totally geeked that they sailed through our solidly zone 5 winter without missing a beat. Both form compact, tidy mounds (at one year in, they're 3-4 inches tall, and maybe 6 inches wide) of beautiful silver, finely cute fern-like foliage and have delicate round pale pink (in the case of ) or white (in the case of ) flowers with a pansy-like eye of darker purple that dance above the leaves on slender stems.

Erodium glandulosum

Erodium chelianthifolium

The two species are quite similar, with E. glandulosum somewhat larger in all its parts and proving to be marginally more vigorous and heavily blooming in the garden, though I think E chelianthifolium. has somewhat prettier (though smaller) blooms, and a stronger silver to the foliage.

Erodium chrysanthum

E. chrysanthum has the best foliage I've seen in this genus, a brilliant silver of the sort people usually resort to annuals like dusty miller to get (though it doesn't show up well in this photo...), on a tidy compact plant that stays under 6 inches tall and slowly spreads to a foot or more in width.

Erodium chrysanthum

 The flowers look white in this photo, but are actually a delicate shade of the palest possible yellow. They're beautiful and produced continuously during the summer, but in all honesty are best described as sparse. This plant is all about the foliage, and the flowers are just a sprinkling of extra goodness.

Erodium carvifolium

Erodium circutarium

Erodium mannescovii

E. carvifolium, E. cirvutarium, and E. mannescovii look so similar that at first I wondered if they were different plants at all... but comparing the three side-by-side, they are distinct, and in the garden their growth habits are noticably different as well. 

All have large, dark green very ferny leaves that form an almost flat mat, only a few inches tall, but one year in, are already over a foot across, and all three are intense when it comes to flower production, blooming heavily all summer long with big masses of brilliant see-them-on-the-other-side-of-the-garden magenta flowers. 

Erodium carvifolium

I'm not usually a magenta fan, but these I like. A lot. They are loud and unabashed and cheerful. Comparing the three in the trial bed, my clear favorite is E. carvifolium Bigger leaves and flowers than the other two, it is also clearly the most vigorous and heathy of the three, and is blooming the heaviest. I do however also like E. circutarium, which holds its flowers more upright than the other two.

I did also put two other species of Erodium in the trial beds, E. chamaedryoides and E. richardii, neither of which made it through the winter... which came as no surprise. If you live somewhere warmer (zone 7 maybe 6) they're well worth growing, tiny, cute, adorable little things. But I think I'll stick with the hardy ones.

Report from the trial beds: Delosperma overwintering

Last summer, I took an unused section of the nursery and turned it into what we're calling the trial beds. The idea is to set out big sections of our collection side-by-side so visitors to the nursery can easily see what they look like in the ground, compare different species and cultivars, and get an instant education on groups of cool plants they might not have ever heard of.

Here is what they looked like just getting started last summer. The first bed has our entire collections of dracocephalum, scutellaria, teucrium (about a dozen species of each), along with some dwarf gypsophila and onosmas. The second bed is our entire collection of Penstemon (clocking in at no fewer than 45 different species and varieties... Yeah. That is a lot.) and the third, not finished in this photo, has asperula, erodiums, and delospermas. Three more beds will hopefully get planted up this summer. (Got a genus or group of plants you'd be curious to see grown out this way? Let me know in the comments and I might be persuaded to put them in for you.)

If you are local, I hope you'll come by and check them out over the course of the summer -- I think they're going to be pretty darn cool. But, since most of you AREN'T local, I'm going to try and give regular reports on what I'm seeing in the trial beds here on the blog.
First up, Delosperma overwintering. Most of the varieties of delosperma we grow are supposed to be hardy. And most of them ARE, provided they are kept nice and dry. Cold doesn't usually kill them, but winter wet certainly does. So I was interested to see what could actually make it through our wet Michigan winter. We do have very sandy soil at Arrowhead, which helps enormously (don't expect this sort of overwintering success if you have heavy clay) but as you can see, these aren't raised beds or rock gardens to give extra good drainage.

So, here are the survivors:

Delosperma eckolonis v. latifolia
D. cooperi 'Dwarf' (Note that the normal D. cooperi did NOT survive)
D. 'Firespinner' (so excited about this one... gorgeous in flower. I'll share later once they start blooming)
D. sphalmanthoides
D. basuticum
D. aff. nubigeanum (If you are unfamiliar with "aff." if basically means that is the name the plant came with, but we're not sure that is really what it is. Honestly we could probably put that on almost ALL the delospermas... Notoriously mixed up in the trade, and hard to figure out if you are not an expert in the genus. Which I'm not.)
D. aff. congestum
D. 'Broncoensis'
D. congestum 'Gold Nugget'
D. deleeuwiae
D. 'Lesoto Pink'

This is, honestly, a much longer list than I was expecting, over half of the plants I put in the ground! It is only data from one winter, of course, but it was a fairly cold winter. Temperatures dropped to -10 F and STAYED there for a few days, with almost no snow cover, in the process killing more than a few plants that had been hardy in the garden for years. Arrowhead sits just on the edge of zone 5 and zone 6 on the new USDA hardiness map, which means that around -10F has been our average winter low for the past 30 years, so this was a fairly representative winter, though of course we can get much colder... there was the year of -26 F, but hopefully we won't see that again for a long time.

I took pictures of all the surviving plants, but honestly they all pretty much look like this one of 'Gold Nugget'

Not much to see at the moment. But I'll follow up with pictures of each of the survivors once they start flowering, and hopefully keep tabs on them on and off through the summer so you can see how they spread, and which ones rebloom.