Zanthan Gardens
Category: Plant Highlights

Retama (Parkinsonia aculeata) forms a small, airy, lime green tree that appears as fresh as spring on even the most droughty summer days. You can use it as a specimen plant or to create a vicious hedge. The smooth green trunks and branches are covered with serious spiny thorns hinted at by one of its common names, Jerusalem thorn. Retama can photosynthesize through its green bark; its Spanish name is palo verde (green bark). From a distance retama looks like it’s covered in stringy green streamers which cast a filtered shade. Having such very small leaves it loses little moisture to transpiration making it extremly drought and heat tolerant. Overall, it has a delicate, feathery appearance. Flowers are bright yellow.

Latin names are a bit confusing as the Parkinsonia clan used to be called Cercidium. The common names are worse as nurseries in Austin usually sell this as retama but it’s not the same as weeping white broom, Retama raetam. The City of Austin Grow Green site hedges its bet and calls it Retama Jerusalem Thorn.

Perhaps, as one reader suggested, it is overused in Phoenix. I imagine that when people first brought it under cultivation in those desert towns they were thinking, “Green! Green! Green!” And it’s such a carefree plant that it’s perfect for those median plantings along highways and outside of subdivisions. However, in Australia it’s an introduced invasive weed.

In addition to being spiny, retama has a reputation for being a messy tree. Mine is too small to make much of a mess. If you have small children, or a small yard, you might prefer to admire retama from the comfortable distance of your car. I’ve neither, so I’ve taken a chance with it. Give me another five years or so and I’ll tell you whether I think it’s a curse or a blessing.
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That last cool and rainy week in May I popped in at Barton Springs Nursery as a reward for my taking my car in for it’s yearly inspection before the sticker expired. My wandering into a nursery is as wise as an alcoholic browsing at a liquor store. The last two years I’ve put myself under a strict plant-purchasing moratorium, taking advantage of these drought years to focus on the hardscaping of the garden in hopes of adding some structure and manageability.

Like everything marketable, plants are subject to human whims in taste, to horticultural fashion. Before me lay all sorts of plants I didn’t know, but the first to catch my eye was a tropical looking plant with lime-green leaves and delicate panicles of violet blue flowers, Duranta erecta. It’s common names are golden dewdrop, or pigeonberry, for its golden fruit which is poisonous to humans but beloved by birds. It is an attractive nectar plant for butterflies and hummingbird. Golden dewdrop is very trendy in Austin this year because it’s been named a Texas Superstar plant.

Disregarding my own advice about buying plants in the summer, seduced by the cool light drizzle stirring up memories of my recent week in England, I bought three of them. After all, they were on sale. [They’re on sale because it’s summer. They’re doomed. Don’t do it! — Your Rational Mind]

Everything about golden dewdrop reminds me of plumbago: its multiple, arching stems form a small fountain of a bush; its five-petaled flowers hang in loose racemes at the tip of each branch; its glossy, green leaves withstand heat and sun. Also like plumbago, golden dewdrop will die back to the ground in a freeze. So, although it is naturally a large bush or small tree, in Austin it will remain a mid-sized shrub. In colder climes than Austin, golden dewdrop is often grown as a potted plant and brought indoors to overwinter.

In its native South America golden dewdrop grows on limestone which means it should be happy in Austin soils as long as it is planted in a well-drained spot and not in heavy clay. (The requisite caveat in all garden writing.) It is reputed to tolerate drought (What do gardeners in Puerto Rico consider a drought?), poor soils, and some shade but it grows and flowers best if planted in a nice garden bed and watered.

In order to get them through the summer, I put the golden dewdrops in the front planter as potted plants. Recently, in order to clear the driveway of the gravel pile, AJM moved the stone into the reconstructed planter until I can use it elsewhere in the garden. Then I thought, hmmm, this looks like a design.
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Garden blogs have been all abuzz this week over lawns. In Austin we’re encouraged to replace our lawns with beds of native or xeriscape plants in order to cut down on our water usage especially if we want to enjoy our yards without being enslaved to a high-maintenance landscape. I don’t think the issue is so cut and dry. Typical homeowners, at least in South “Keep Austin Weird” Austin, don’t spend a lot of time watering or mowing their grass. Replace what passes for lawns in a lot of Austin with other plants and I think a lot more people will be spending a lot more time using a lot more water.

Those people unfortunate enough to live in places like Circle C where they’re required by neighborhood covenant to keep the grass greener on their side of the fence, even in periods of extended drought when we are under rationing, I’m guessing are rich enough to pay other people to do the maintenance. (How will this dynamic change with the current crackdown on illegal immigration?) Are they even allowed to replace their lawns? Ah, I digress.

When I acquired this house in April 1993, the entire front and back yards were covered in St Augustine grass. I was happy to have inherited an automatic sprinkling system until we got our first water bill. After I recovered from the shock and swore never to use the system again, I bought a sprinkler to fit on the end of the hose and watered only the healthiest parts of the lawn. In June of 1993, one of the cedar elms snapped in half during a storm. Suddenly the north quadrant of the backyard was baking in full sun. I let the marginal grass die, covered it with mulch, and began planning a wildflower meadow.

Over the next few years, I planted buffalograss, bluebonnets, larkspur and various small bulbs like rainlilies, species tulips, and fall crocuses. The meadow looked great in the spring, but very patchy and weedy the other 9 months of the year. Although buffalograss spreads by runners, it forms clumps rather than a smooth lawn. Therefore I don’t think it looks particularly nice mown. And the same characteristics that make it a haven for small bulbs and flowers, provide the same haven for weeds. I’m constantly battling horse herb (which grows up over buffalograss, shading and killing it) and other undersirables.

The blades of buffalograss are narrow and sharp. It is not a grass to wiggle your toes in or lie back in and watch the clouds. Over the years, various trees on the border have made the once sunny meadow area quite shady. Buffalograss does not like the shade at all. I like its color of dry hay (of green tatami), but in the worst heat of summer, it is not a color which is restful to our parched eyes.

In contrast, the deep green coarse blades of the St Augustine grass makes me want to fling off my shoes and throw myself back on it in delight. I do not spend a great of water on the St Augustine lawn. Unlike some other grasses, St Augustine likes mulch. I learned this from watching how it took over any path I made around the yard. So every time I see a bare spot or thin grass, I mulch it with a combination of Dillo Dirt and Texas native bark mulch. I don’t feed it any lawn food and it rewards me by not growing too fast.

I think of St Augustine as a southern grass. It evokes summer days under shady live oak tree with the whine of cicadas filling the air. Buffalograss creates a praire mood with its tall, wispy blades and loosely filled clumps undulating in billowing waves under a withering wind. Austin sits on Balcones Fault and shares characteristics of both the old South and the desert West. I pleased to have a little of both in my backyard.

I’ve gotten rid of all the lawn I’m getting rid of. Compared to the rest of the yard, it is low maintenace especially in ratio to the pleasure it provides.

I like that the Texas Aggies classify red yucca as an “evergreen shrub”. Unless you garden in the American southwest, you probably think of shrubs as multi-stemmed woody perennials, such as roses, azaleas, yew, box, and lilacs. But down here in Texas, we have to use a bit of imagination. Truth be told, red yucca (Hesperaloe parviflora) isn’t a yucca either.

The last few years red yucca has become very popular in commercial landscapes and median plantings around Austin. They really strut their stuff in a mass planting where the pale red flowers seem to float like a cloud of butterflies above the green spikey base.

I don’t have room for a mass planting in my garden, so I found it a bit of a challenge to site a single plant among the cottage garden plants. I stuck it in a sunny spot between the ‘Penelope’ and ‘Prosperity’ roses and I don’t think it quite works. However, I’m happy that after four years, it has finally decided to bloom.

A single red yucca almost disappears into the foliage of more traditional shrubbery. It works better in a starker landscape or when planted en masse.

Red yucca is reputed to attract both butterflies and hummingbirds, but I haven’t noticed either around my plants. [2008-06-13. Saw a hummingbird on the red yucca this morning.]

I think red yucca is better described as heat-tolerant, than drought-tolerant. High temperatures don’t seem to bother it, but in Austin it requires some supplemental water during the worst of summer to thrive. Just be sure that it has good drainage. (One thing to remember about so-called drought-tolerant plants…just because a plant can tolerate drought conditions doesn’t mean they perform their best. It’s more of a comparitive term. A red yucca can get buy with a lot less water than a hosta. But it doesn’t mean you can just plant a red yucca and forget about it.)

Red yucca forms clumps and you can divide them in the winter. I found it easy to start red yucca from seed, too. However, it grows very slowly. The seedlings I started two years ago are only six inches tall.
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My “Scott’s Ruston” rose is a bit of a mystery. I bought it from Barton Springs Nursery in 2001, but I’ve never been able to find a reference to it in any book or online. Something about the label made me think it is a found rose.

In Australia, the David Ruston Rose Centre is home to the National Rose Collection of Australia. (I suspect from all those capital letters, it’s an official collection.) Apparently they have 4000 varieties of roses, but they don’t provide a list, so I can’t find out if one of them is named “Scott”.

“Scott’s Ruston” is very similar to ‘New Dawn’ which makes me wonder if it is a sport. The flowers are the same shape and color, but the petals on “Scott’s Ruston” seem to have a more rounded edge. They both open flat and fade to the palest pink. I can’t rule out the possibilty that both these roses are ‘Ne. Dawn’ roses and that “Scott’s Ruston” was mislabled at the nursery.

2006-04-23. The same instance of “Scott’s Ruston” rose after it opened. Cooler weather after the rain this week meant the roses looked nice for a couple of days each.

“Scott’s Ruston” is less vigorous than ‘New Dawn’, but that might just be because I planted it in an unfortunately shady spot under a cedar elm tree. In the same amount of time, ‘New Dawn’ has clambered all over the fence and is broaching a Texas mountain laurel, while “Scott’s Ruston” is just starting to arch over the fence.

After more than four years, “Scott’s Ruston” might finally have settled in. This year half a dozen roses opened at once.

Does anyone else grow this rose?

The last nine months or so, I’ve neglected the garden. Some plants, like the roses and irises, really show it. Other really tough plants have surprised and encouraged me. This spring I’ve been very thankful for Acanthus mollis. Auralea japonica, Rhaphiolepis indica, Tacoma stans, and Salvia farinacea. Without them, I’d have no garden at all this year.

Yesterday I noticed a the first flower of the season on Salvia farinacea ‘Indigo Spires’. Thanks to the water that sprays over the fence when my neighbors water their lawn, my salvias have formed nice mounds of green this spring. I decided I should finally cut off the long arching stems from last year. I should have cut them way back last fall.

One advantage of my lazy housekeeping is that salvias self-layer and root wherever the joints touch soil. In my garden, plants die every year and new ones replace them. I let them grow where they’re happiest and they’ve arranged themselves around the cedar elm in the back of the stump garden. I do absolutely nothing for these plants except mulch them with leaves in the fall and prune them back once a year.

Gardeners in Austin are typically crazy for salvias. They come in many varieties, sizes, and colors. In addition to being heat-loving, salvias have the reputation of being deer-resistant. (I can’t say since there are no deer downtown). One drawback I’ve heard, however, is that some salvias dislike Austin’s alkaline soil. I haven’t noticed that problem either in my garden or around town. I’ve tried a couple of other salvias, but Salvia farinacea has proven the most carefree in my central Texas garden. One plant, eleven years. That’s got to be a record in my garden. Only the plumbago, which I bought and planted on the same day, has done as well.

By the way, I’ve had a hard time trying to peg down exactly what type of salvia I’m growing. When I bought my one plant in 1995, I wrote down Salvia farinacea ‘Indigo Spires’. Apparently the salvias cross-pollinate easily and some sites list ‘Indigo Spires’ as a hybrid, not a cultivar. As for common names, I’ve found both mealy cup sage and mealy blue sage and even plain mealy sage.
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Those opportunistic plants, the weeds, have responded quickly to Sunday’s rain. The henbit was the first to flower. A winter annual considered by many to be a weed of turfgrass, henbit thrives in the damp and so is at home in our clay soil during the winter. AJM likes the little pink flowers, and so do the butterflies. So I always leave them a little bit of it in the meadow–until some other flowers are blooming.

2006-01-24. Henbit. Austin, TX

Henbit does get straggly fast as it sprawls over the bluebonnets. Then it’s definitely weedy and I swear that next year I’ll nip it in the bud. As soon as it gets hot, though, it disappears on its own, so it’s never any real problem in our central Texas climate.

In Japan, henbit is one of the seven herbs of spring and is eaten as a tonic on January the 7th. This tradition goes back to those days before frozen foods and refrigerated trucks, when people suffered vitamin and mineral deficiencies without fresh greens in the winter.

Perhaps like other oft-maligned plants (I’m thinking of dandelion and nettles, Margaret), we will soon be paying top dollar for henbit in Central Market’s “spring mix” salads.

Dateline: 2005-10-09
After flowering for two summers, the mother plant died. Slowly its stalk rotted away and the pups (some of which were full-grown plants by this time) began to fall away from the center.

2005-07-28. Even in late July, the blue-green banana leaves looked crisp and fresh. They never turned brown or wilted like the brighter green canna. However the number of pups was getting out of hand.

As today was the second of two perfect fall days, I decided it was time to dig up and replant the pups. I soaked the ground thoroughly to make it easier to get through the hardened clay. Then AJM and I began digging around the perimeter and trying to prize up the mass by getting the fork under the roots. The whole mass is fleshy and breaks easily. All we succeeded in doing is snapping the top of the banana plants off the roots.

In the end it was a banana tree massacre. A score of large banana trees lay rootless on the ground. Half a dozen smaller ones came away with a little bit of root. And what about the roots? If I replant them, will new pups spring up? Are banana trees like Tradescantia in this respect. I’ll try it and see and report back.

I was very depressed after destroying my banana plants. I had to keep telling myself that they were all going to fall over and die anyway and they had outgrown the space and were crushing the plants near them. Still, there’s a big empty spot in the garden where once was the most beautiful green.

I started with one and I have more than one now. If even one pulls through the winter, all will have worked out in the end.
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I don’t know why I haven’t been a big fan of gladiolus before, unless maybe it’s their movie association with mobsters’ funerals. Last year, the photos in the Dutch Garden catalog seduced me into buying some Flevo gladiolus, which are smaller and more compact than normal. And now I’m hooked. They bloom along with the cannas and other heat and water-loving tropicals. Now that I’ve devoted a special plot to all my high-consumption plants, I don’t mind doting on them.

I was surprised how pretty they are. Has anyone every described a gladiolus as “delicate”?

Nursery Description. “Creamy, pale yellow blooms deocrated with soft rose. Plant 4 to 5 inches deep and 5 to 6 inches apart. Full sun. Height 22-28 inches.” Souce: Dutch Gardens.

Tags: gladiolus, flower, bulb, garden.
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In 2000, I bought three similar tall bearded irises: ‘Alizes’, ‘Strictly Ballroom‘, and ‘Altruist‘. The ‘Alizes’ were $6.00 each (actually $3.00 with Schreiner’s discount factored in). One characteristic that distinguishes ‘Alizes’ is the full, cupped shape of its brilliant white standards. (Warning: the Schreiner’s photo shows an unreal shade of bright blue, which it isn’t. ‘Alizes’ is a deep blue tending toward violet.)

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