Frost Warning (yes, another)

While Lafayette, Orinda and Moraga are receiving less rain and wind than predicted from this series of storms, the National Weather service is now forecasting lows of between 32 and 38 degrees this coming Tuesday through Friday mornings.

Your microclimate might even see temps in the high 20s; frost-tender plants may suffer unless covered through Friday morning. Time to roll out the frost cloth and sheets again.

Frost Warning

Lamorinda folks: tomorrow (Wednesday 1/2) is looking to be *very* cold. But Thursday AM 1/3 will be colder! Depending on your microclimate, we could see 28 degrees or lower. Cover your frost-tender plants tonight and tomorrow! If they’re in containers and easily moved, drag them closer to the house and cover.

Looking forward to warmer overnight temps (and RAIN) beginning Saturday.

Happy new year!

Early tomorrow morning it will get cold in Lamorinda

The National Weather Service is forecasting overnight (tonight, Friday November 9th, into Saturday morning) lows tonight in the high 30s. Certain microclimates in Orinda, Lafayette and Moraga may see 35-degree temperatures.

This is very early in the season for temperatures like this. It’ll mean the end of tomatoes, peppers, cucumbers and similarly warmth-loving vegetables and fruits. If you have basil in pots, move it indoors in front of a sunny window to extend your growing season.

Other tender plants in pots should be moved closer to the house, preferably in front of sliding glass doors, when possible — or inside, where practical. Placing a light cotton towel or some old shirts over them won’t hurt.

Landscape plants in the ground (non-natives, fruit trees, etc) will benefit from being draped in frost cloth, or, at very least, a thick cotton bedsheet or two.

For the latter, I find it more effective to drive three stakes taller than the plant around the plant, then drape cloth over them so it’s not touching the leaves. And it’s best if the cloth is long enough to touch the ground.

This will be the coldest night of the week and the coldest night we’ve seen since March. Plants aren’t ready for this kind of weather, but we can help them through it.

Leaf Blowers

People often complain about the noise from gas-powered leaf blowers. This 2017 article spells out the other health risks for those who operate them. Not only are the emissions toxic, but up-to-270-mph concentrated flows disturb topsoil and send animal fecal matter and settled particulates into the air.

If you use a leaf blower, consider a battery-powered model and try to limit your use to hardscapes. And wear eye and ear protection and an N-95 (when available) mask, or, at least, a KN-95 mask.

Growing Orchids Outdoors

A mounted Laelia orchid hanging from an arbor in Orinda.

What orchids can survive outdoors year-round in zone 9B / Sunset zone 14 — the conditions that distinguish our Lamorinda microclimates?

A select few can make it through our winters — and summers. Depending on where you live, most will need to be covered and/or moved closer to the house once the temperature goes below 40 degrees, especially when conditions are also wet.

Terrestrial orchids planted in the ground sometimes do better than those in pots, because they’re better insulated. However, orchids in pots drain better, because orchids with roots in standing water and, well, mud are not happy — especially in temperatures under 50. Pots also equal portability — being able to move an orchid closer to an outside wall of your home can make a big difference. The best place for a chilled orchid is in front of a sliding glass door, where the most radiant heat exists during the coldest hours of the morning.

Cymbidiums in pots are likely your best bet. But even they can suffer when the thermometer drops under 40, especially when they have flower spikes in mid/late winter. Over the past couple winters I’ve resorted to wrapping the buds in layers of paper towels enclosed by rubber bands, then covering the entire plant in frostcloth.

The question is often one of duration. One 38-degree night? Maybe okay. But two or three, with no fabric to protect the plant from frost? That could be a problem.

A Masdevallia hybrid in a teak basket.











I’ve had good luck with mounted Laelias (although they can require extra effort to keep moist in summer) and, to some degree, Masdevallias. The latter, when in pots, will need to be kept fairly dry — most masdevallias can handle cooler temps, but not cold AND excessive moisture. Even cooler-growing species will need to be kept close to the house when the chill clamps down overnight.

There are other members of the Pleurothallid alliance (cousins of Masdevallias) that are more robust. Certain Restrepias, for example, do fine as long as (yes, again) they’re within a few feet of the house.

Another important element of raising orchids in colder climates is to stop fertilizing in late summer. It’s not wise to force new, tender growth when the nighttime temperatures are heading to the low fifties. I generally stop fertilizing in late September, with the exception of Cymbidiums — I switch to a 6-30-30 formula, especially if they’ve yet to develop flower spikes. If they do, I stop fertilizing completely.

I’ve been growing outdoor orchids in the Bay area for 25 years, and in the East bay for 10. Through experimentation and trial and error I’ve arrived at certain species and hybrids that can make it through the worst our climate can deliver. Contact me at paul at dobiemeadows dot com if you’d like to discuss which outdoor (and indoor) orchids can survive — and which can thrive — in our challenging conditions.

Running Bamboo – Mitigation Methods

Bamboo is seductive in myriad ways.

It’s graceful, fast-growing, disease-resistant, and (deceptively) low maintenance. And the running — as opposed to clumping — varieties spread … often faster and further than we’d like.

Most running bamboos have a three-year establishment cycle.

Year one: it sulks
Year two: it awakens
Year three: it runs.

All bamboo, whether running or clumping, has a nose for water. Running bamboo, in particular, can sniff out water and charge headlong, underground, in its direction. Its rhizomes — the lateral roots that send up shoots yards away from the mother plant — will not be denied in their quest for moisture. If you’re regularly watering, say, a red-twig dogwood (Cornus alba cultivars, et. al) 15 feet away from a grove of running bamboo, you can bet the rhizomes will reach the dogwood by the third or fourth year, especially following wet winters.

For this reason, placement is the optimum criteria for bamboo and any adjacent plants. Running bamboo is best grown in a strong container (i.e. not terra cotta, or plastic) placed on top of a thick cement paver. If you still insist on planting it in the ground, it’s best to dig a 30-inch (at least) deep ditch entirely around the plant and monitor for rhizomes aiming to run. Cement berms work for awhile, as do resin boards sunk three feet deep around the plant, but I’ve seen rhizomes go over, under, and, with cement, THROUGH barriers. The best way to monitor runaway rhizomes is to use the ditch method.

So, after all this, let’s say you go ahead and plant a variety of running bamboo in the ground with no ditches, containers or barriers. Before four years have passed, your neighbor reports seeing bamboo shoots emerging from the ground on his side, close to your mutual fence — in the middle of his prize azaleas.

Now what?

Assemble these tools:

1) heavy gloves and safety glasses/goggles
2) spade
3) trowel, or hori-hori or cultivator/hoe hand tool
4) crowbar
5) reciprocating saw

This is a specialized job but can be done by most homeowners with the proper tools and a bit of surplus energy. It helps to undertake the task on a cloudy day that’s not too hot; spending a dusty weekend sweating, on your knees, crowbarring three-inch diameter bamboo rhizomes isn’t something I’d recommend to a friend.

Don’t soak the ground in an attempt to make digging easier. This just makes the dirt expand, and (obviously) become muddy and, actually, more difficult to work with. Too much water also helps any rhizomes you don’t find to spread faster. Sprinkling a bit of water on the work site tends to help keep the dust down, so there’s that. Some may also find a dust mask helps deal with airborne particulate matter when digging in dry dirt.

Find the end of the rhizome. It’s usually just beyond the most recent sprout. Dig down, gently, using the trowel, until you locate the rhizome, then work around it with the hori-hori or crowbar until you find the tip. This will involve digging a narrow, somewhat deep trench — rhizomes like to dwell about 4 to 10 inches underground, depending on shade levels and corresponding soil moisture/depth and density.

Some find using a spade or shovel better for this phase of the work, but be careful not to cut the rhizome with larger digging implements — it’s easy to lose track of the rhizome when you resort to blunt-force digging. I make every effort to avoid cutting or breaking the rhizome until it’s traced back to the plant. It’s also easier to pull up a rhizome when you have a longer length of it you can wrap your hands around.

A crowbar is an excellent, somewhat-neglected digging and scraping tool, ideal for problem areas where detail work is necessary and a shovel is overkill.

Begin pulling the rhizome up, pausing every few inches to wedge the crowbar under it to coax free the threadlike roots anchoring the main rhizome to the dirt. Get as many of those roots as you can and pull them out, and DON’T leave any pieces of rhizome — throw them all in a bucket for greenwaste. If (often when) the rhizome breaks while you’re pulling it up, dig down and start again. Using this method, trace the rhizome back to the mother plant.

It’s usually hard, dirty work.

Once you finally get within 12 inches of the main plant, you will probably have to use large loppers or even the reciprocating saw to terminate the thick outbound rhizome.

This is the perfect opportunity to dig a circular ditch around the mother plant. The ditch should be at least 30 inches deep and about a foot wide. Prepare to find other outbound rhizomes…and repeat the steps above.

Maintain the ditch regularly — rake it out and go in with a shovel and excavate any dirt and debris that has fallen in over the subsequent months. Any leaves and organic matter in the ditch will act as mulch and keep the ground moist — a perfect place for eager rhizomes to hide and roam. Examine the exposed soil adjacent to the bamboo and prune off any emerging rhizomes.

There are people who will use Roundup on the outbound rhizomes rather than do the dirty work of pulling them out. I avoid using it (Remuda, Roundup, or any other manifestation of glyphosate) due to its toxicity — this is subject deserving on an extensive blog post of its own — but if you insist on treating the rhizomes with Roundup, opt for the roll-on gel variety. It eliminates the possibility of overspray and lessens the temptation to just drench the soil around the rhizome.

And remember: since Roundup is a systemic herbicide, do not treat any rogue rhizomes with it unless you’ve first severed them from the mother plant. Doing otherwise risks poisoning the entire clump of bamboo.

If you have a runaway bamboo (or even a well-behaved) grove and need a consultation on control and mitigation, please contact me at paul at dobiemeadows dot com. I’d be happy to come out and recommend some solutions.


It must be noted that this method of bamboo mitigation was taught to me by Kenny at Moraga Garden Center, Moraga, CA, whose knowledge, patience, and tutoring continues to be indispensable in my ongoing efforts to become a better gardener.


…and thanks for visiting.

I offer consulting services to customers in Moraga, Orinda, and Lafayette, California. I am no longer adding clients, as I work solo, and my current roster of weekly maintenance work is maxed out.

I will continue to take on smaller tasks, such as dividing and repotting orchids, as well as consulting.

I can be reached at the Contact heading under the Pages sidebar to the right of this post.

I have over 35 years of experience gardening and landscaping in Northern California, with the last fifteen years in Lamorinda. I’ve been working professionally since 2018.

I specialize in native cultivars, pollinator gardens, organic vegetable gardening, and succulents, as well as orchids, bamboo, bromeliads and other exotics. I have significant experience with dividing and repotting orchids and bromeliads, water-wise landscaping, xeriscaping, drainage issues, seasonal pruning, fertilization, defensible space consultation / mitigation, gutter cleaning, brush clearing, and bamboo thinning / maintenance.

I’m licensed to sell nursery stock in Contra Costa County by the state of California. I buy, propagate, and raise well-tended native and exotic plants in my yard near the Orinda/Moraga border. Appointments can be made via the Contact link to the upper right. The selection is of particular interest to orchid and bromeliad fans.

* I’ll consider travel outside the Lamorinda area for longer-term / more extensive projects, especially if they involve native plants, habitat restoration, and invasives removal.

Bamboo Debris and Fire Danger

Bamboo is an acceptable choice for a fire break. Its canes are low in oils and don’t burn easily.

Its dead sheaths and leaves, however, are very flammable. The local fire department here in town has actually listed new bamboo plantings as “prohibited” for this reason.

A major element of maintaining a healthy grove of bamboo is regularly raking all fallen debris. Keep the ground around your bamboo — as well as the branches — free of dead leaves and sheaths. This not only minimizes fire danger, but also enables you to water the soil more evenly, and lessens the chance of mold and insect infestations at the crown (the spot where the canes meet the soil and root system/rhizomes).