I LOVE ornamental oxalis in the garden!
Before you all think I’ve lost my mind, I’m not talking about the horribly invasive oxalis weed that threatens to take over lawns and gardens everywhere.
I’m talking about the many varieties of colorful and well-behaved ornamental oxalis hybrids.
The ornamental varieties often get overlooked in the nurseries, not because their foliage isn’t captivating (which it is), but because people are naturally suspicious of a plant named oxalis.
Poor oxalis – just saying the name causes many gardeners’ blood to run cold.
So worried gardeners pass on by the 4” pots at the nursery, never getting the chance to see how incredible these little beauties can be in their garden.
Over the years, I’ve planted several varieties in my garden and thought I’d share with you those that have proven to withstand the test of time, reliably returning each spring.
Oxalis siliquosa ‘Sunset Velvet’
Quite possibly, the most beautiful ornamental oxalis of all is ‘Sunset Velvet’ (also in the photo above.)
The delicate clover-like foliage always seems to be changing color. In spring, the leaves emerge a bright green color, complemented by red stems.
But, as the temperatures warm up, the lime green turns to shades of terra cotta and peach.
Colors that perfectly complement the zillions of happy little yellow flowers that start to make their appearance.
And talk about long-lasting – these flowers bloom for months at a time!
As fall and winter settle in, the shades intensify with ‘Sunset Velvet’ putting on its best show yet, with rich gold and amber tones.
One of the things I appreciate most about ‘Sunset Velvet’ is how it blends with just about any container you might have. Terra cotta, ceramic, tile, zinc – you name it, this variety is a natural companion.
‘Sunset Velvet’ has been evergreen in my zone 9 garden, lasting 4-5 years before needing to be replaced.
Planted in bright shade, it has survived the hottest days and the coldest nights (down to the high 20’s) without a complaint!
It grows to 10” or so, and when planted in a container will gently cascade over the sides.
Oxalis spiralis vulcanicola
This is another variety that does well in zones 8 and up, growing to a tidy 15” x15”. As with most other oxalis, it blooms spring through fall with the cutest yellow flowers.
I’m a sucker for any plant with maroon foliage.
The dark burgundy color (really, it’s almost black!) is a fantastic way to add the illusion of depth to a garden, as the nature of the color will visually recede.
While burgundy recedes, lighter colors (especially bright green or silver) will appear to move forward, therefore creating the illusion of depth.
I love this combination for a few reasons.
Not only does the dark maroon variegation of the viola ‘Heartthrob’ harmonize with oxalis’s burgundy foliage, but the bright green color helps to emphasize the ‘depth’ that I was referring to, above.
I’m particularly fond of planting this variety in containers made of similarly dark materials, like the faux bois container above, or my burnished copper window box.
Oxalis triangularis ‘Charmed Wine’
The dark plum foliage of ‘Charmed Wine’ is much larger than the above varieties, resembling a giant, traditional shamrock.
Growing from tiny bulblets, this variety has reliably returned for many years when planted in various containers.
I have one plant that has been with me for eight years now, due to the fact that it’s one of the most cold-hardy oxalis out there – hardy down to zones 7b.
And those flowers! The tiny soft lavender blooms start appearing in early summer, lasting for several weeks. To me, they’re the icing on the cake.
I’ve had many people tell me they’re not quite sure how to incorporate the vibrant (and somewhat garish) tones of the ‘Charmed Wine’ foliage within their containers.
I like to pair them with a plant that has similar (yet subtler) shades, like this plectranthus ciliates. The result is an unexpected color combination that helps tone down the intensity of the ‘Charmed Wine’ foliage.
The triangularis varieties tend to fold their leaves down at night, forming tight little clusters, re-opening again in the morning, resulting in their common name of ‘Butterfly Shamrocks.’
Oxalis deppei ‘Iron Cross’
While most ornamental oxalis varieties are from South America and South Africa, ‘Iron Cross’ hails from Mexico.
However, similar to triangularis, above, this oxalis is also a tuber with little bulblets. This translates into being a better choice for colder climates – when dormant, they’re hardy down to 10-15 degrees.
Similar to oxalis vulcanicola, the burgundy and bright green variegation make this variety a spectacular choice for creating harmonious color echoes.
I’ve even read that this variety is edible in moderation, with a lemony flavor (not sure if all are edible, or just this one.)
Oxalis corniculate – the dreaded weed!
I can’t possibly write a post about oxalis without mentioning oxalis corniculate – the terrible, horrible weed we’ve all encountered in our lawns and gardens.
Removing them can be a nightmare, but especially if you don’t act fast.
I have the best luck when I dig them out the second I see them, hopefully while they’re still young and compact.
If you wait too long, they’ll quickly set seed, and away they go! It’s also imperative that you get every last bit of their roots, otherwise, they’ll grow right back again.
As you can see from these photos, the CobraHead has a wide, spoon-shaped end that has a pointed tip (they refer to it as a ‘steel fingernail, a perfect description!)
It’s that design, coupled with the steel blade, that allows you to quickly uproot the weed, along with its entire root ball.
CobraHead is an amazing family-run business that makes all of their tools in Wisconsin, using environmentally friendly materials whenever possible (you can read more about why I love this company and this tool, here.)
In addition to the above methods, I also make sure to use a hefty layer of mulch (3” minimum) to suppress all weeds.
While oxalis will still grow up and through the mulch, by the time it reaches the top, it’s usually so leggy it’s much easier to remove.
More varieties to try
Not wanting to end this article on a sour note (talking about the evil oxalis weed!), I thought I’d highlight a few other spectacular varieties.
I personally haven’t grown these hybrids, only because I’ve never seen them offered in any nursery.
But if I find them, you can be sure I’m going to give them a try!
Oxalis ‘Candy Cane’
Oxalis corymbose aureo-reticulata (Gold-Veined Shamrock)
I can imagine some refreshing color combinations as a result of the gold veins in these leaves.
I’m thinking yellow flowers (columbine, perhaps?) or combining this variety with the oxalis spiralis vulcanicola shown above?
Available from Glasshouse Works
Oxalis palmifrons (Palm Leaf False Shamrock)
Is this foliage incredible, or what???
No wonder it’s called the ‘Palm Leaf’ oxalis.
Plant Delights no longer carries this, but their site has some pretty interesting information on it – click here to read.
There seems to be several sites that sell this, including Telos Rare Bulbs. I’ve never ordered from this site, but they seem to have the widest collection of ornamental oxalis I’ve seen yet.
Well, that’s it for today. Tell me, do any of you have a variety not mentioned here?
If so, please share your favorites in the comment section!