Herself's Houseplants

THE lure of lithops begins with a double-take, the realization that these pebbles are actually plants, alive and growing. See these succulents in a specialty nursery — or run across them at Home Depot or Lowe’s — and you may feel like a gem collector who can’t resist a few more cabochons. Perhaps the mottled pink ones? Or maybe the lovely dove gray flecked with green?

Lithops can be almost as tough as stones too. They’ve adapted to the most inhospitable growing conditions imaginable: sandy deserts that get no rain most of the year. Ascetics of the plant world, lithops spurn rich soil and regular water. Conventional wisdom about how to keep a plant happy doesn’t apply. . . .

“The secret is to observe them, which, by the way, is not a chore but a pleasure,” Hammer says.

He suggests growing lithops in coarse, fast-draining soil. In their native habitat, the plants thrive in mineral-based soils poor in organic matter, and they receive only a few inches of rain a year. A good soil mix is more white than brown: Think one part commercial potting soil with twigs removed, and two parts perlite or pumice. If you use perlite, which floats, add a top dressing of gravel. The addition of decomposed granite will help toughen the plants.

Grow lithops in pots, not garden beds. Indoors, Hammer says, “they grow very well in a bright eastern window, close to the glass.” A southern exposure will work as well; west isn’t quite as good; and northern will invite failure.

The type of pot doesn’t matter much, but if you’re concerned about overwatering, clay will keep them drier — and will last longer than plastic.

The plants need four or five hours of full sun daily. Given too little light, lithops will elongate. Morning sun is ideal. Protect them from scorching afternoon sun in summer. If new plants have been in a greenhouse, introduce them to sun gradually so they don’t burn. One trick is to drape them with a paper napkin for several days.

Eccentric little rock stars

I had not heard of these plants until recently. What a cool plant!  I can’t wait to try some. I’ve seen them in dish gardens at the flower shows.

Australian orchids are engaged in an arms race, using sensory overload to seduce male insects. Macquarie University PhD student Anne Gaskett has discovered just how they do it. Her work is important to the conservation of orchids and the control of economically important agricultural pests.”I have accumulated the first compelling evidence of an ongoing and escalating arms race between orchids and their unwitting insect pollinators,” Gaskett, says, “Over generations the insects learn to avoid having sex with orchids, and this means only the most persuasive orchids reproduce, which drives the acceleration of orchid subterfuge.”

. . .Gaskett has been studying the hardworking Orchid Dupe wasp (Lissopimpla excelsa), which is fooled into copulating with not just one, but five native Tongue Orchid species (Cryptostylis) in urban and regional Australia. All the Tongue Orchid species mimic the female Orchid Dupe wasp. But, to the human eye, they look quite different.. . .Australian orchids’ sneaky sex tricks

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Anne Gaskett