This week on the hillside, we'll exceptionally have only one workparty, on Sunday, from 10 a.m. to 12 p.m.

Meet-up: South entrance of Regency Court (GPS/address: 1531 Regency Court, El Cerrito).

We usually meet rain or shine (yes, well-equipped, and sipping a hot drink afterward — rainy workparties are amazingly satisfying), but we cancel during Spare the Air Alerts, and we have one tomorrow on Wednesday as usual.

So we'll only meet Sunday for a WW Party: Walk Workparty. We'll do a small walk starting from the south entrance of Regency Court and looping back through the north entrance. Along the way, we'll remove the broom that defies us near the trails.

There will also be an opportunity for a science, or "I wonder," project. This year we seem to have more genista broom moth caterpillars (Uresiphita reversalis) than usual — many of the broom plants are stripped bare and still covered in the culprits themselves. While we appreciate the help, this biocontrol agent (introduced to California in the 1960s from the southern/southwestern US and Mexico) doesn't distinguish between broom and our native bush lupine (Lupinus albifrons): it happily defoliates both.

We used to have a beautiful stand of lupines at the "Cyclops Garden" (another intriguing name to make you come check by yourself) but they seem to have all died, and we're wondering whether that's from the caterpillars or simply natural senescence.

Kids with a terrarium at home who are interested in an experiment could bring home a few caterpillars along with leaves from both silver bush lupine (from a garden) and broom, to see whether the caterpillars show a preference when given a choice. They could also test other plants in the pea family to see what else the caterpillars like to eat — or branch out and try other plant families entirely.

We'll also collect coast tarweed seeds, which are especially abundant in one area. They're great candidates for restoration projects:

• Fast-germinating and easy to establish from direct seeding — low-maintenance

• Deep taproot that improves soil structure and helps outcompete annual grass invasives (Bromus, Avena) in early succession

• Excellent late-season pollinator resource — blooms May–August, filling a nectar gap when many other natives have gone dormant

Hope to see you on Sunday!