4 Degrees of Separation

What a difference four degrees makes.

That's the difference in latitude between my office in Palo Alto, Calif. (37.4 degrees, just south of San Francisco) and my current vacation spot in Carlsbad, Calif. (33.1 degrees, just north of San Diego).

Up north, we can't grow Jacaranda mimosifolia very successfully due to our typically frosty and occasionally freezing winters. Down here, the tree's vibrant lavender blooms are pretty much ubiquitous this time of year.

Up north, our soil is heavily influenced by at least four local ancient volcanoes — mounts Diablo, Hamilton, Tamalpais and Sonoma — with a resultant fertility that made today's Silicon Valley the original "Valley of Heart's Delight." Down here, with the nearest volcanoes some 4–5 hours away, the local soils are much more estuarine, sandy and lacking the minerals and clays that nourish "exotic" plants.

Up north, Palo Alto averages about 15" of rain annually, contributing to a mostly foothill woodland native plant habitat bordering on evergreen forest. Down here, Carlsbad averages about 7" of rain annually, creating a predominantly coastal sage scrub community.

Up north, our average summertime high temperature is above 78° Fahrenheit. Down here, the average summertime high temp is just under 74°F. However, thanks to the famous San Francisco fog, at night we can drop 22°F — while closer to the equator, Carlsbad drops only 10°F.

Obviously there are pros and cons to each latitude, but you can see how just a few degrees of separation can significantly affect environments and lifestyles. Where would you rather live? And if prognostications of global warming expanding the equatorial zones are correct, and Palo Alto comes to resemble Carlsbad and Carlsbad comes to resemble Puerto Lobos, how would your lifestyle change?

Never Do This To Your Tree

The interface between "developed" spaces and "protected" ones is an increasingly hot topic. Lots of properties around here abut open space harboring coast live oak (Quercus agrifolia) trees; I recently came across one of these California natives living on county land just across someone's property line, and growing at such a tilt to push against the residential wall that post-dates it by probably 20 years.

Now, these trees are only slightly more precious than gold around here, and this tree in particular is under county care; so in such a case usually the wall would be sacrificed to the cause. However, in this case someone has decided to adjust the tree instead. But by cutting through the protective bark and into the cambium and even heartwood of the tree, they've severely interrupted the flow of water and nutrients from the roots up the trunk to the foliage. And this is major surgery: deep and rough cuts which are unlikely to heal well (if the tree can muster the energy to heal them at all before it dies).

I'm sure I gasped audibly when I saw this, and the homeowner was equally shocked to learn about it. No one seems to know who made the cut, or when, although it certainly looks fresh. Trees are remarkably resilient, with the ability to compartmentalize wounds and adapt to adversity. But with about one third of this tree's vascular system removed, I would guess it has a very, very poor prognosis indeed.

A Tale Of Two Roses

So your rose bush is blooming magnificently. Bright, big flowers… glossy green leaves… gosh, it's doing so well it's actually blooming in two colors this year!

Uh… not actually.

In fact, if your rose bush is blooming in two colors, I'll wager that one of them is a deep maroon, a little smaller than the other, a little lower on the bush. Probably a little something like this:

If so, you don't have one rose flowering in two colors: you have two roses.

See, most roses sold and planted in California are hybrids — genetic crosses between two different varieties. Not at all Frankenflowers, they're bred this way to give us distinct joy: brighter flowers, glossier leaves, repeat flowering, greater resistance to disease. You can't have it all, though, and what makes them beautiful upstairs makes them weak downstairs.

Enter that miracle of modern ancient technology, grafting. By splicing that gorgeous body onto robust roots that can handle frost, rot, nematodes, fungus, drought, etc., humans figured out that we can have it all.

The only problem, and it's really just a minor one, is that those roots are — by definition — more robust than the body. And just like the body, their prime directive is to grow. Which means you get robust growth… just from the rootstock, not the body.

So those smaller, maroon flowers are "suckers" growing from the rootstock, most likely a variety named "Dr. Huey" (named after a prominent early-1900s rosarian) that is used for almost all California-grown hybrid tea roses because it can handle poor soils, shade, cold, and disease (although it has shown some susceptibility to nematodes in Florida).

Unfortunately, although "Dr. Huey" is beautiful in its own right, if left unchecked its vigor will sap the plant's energy from the more desirable body, the one you presumably bought the plant for in the first place. To prevent this fate, prune the suckers back as close to the primary cane as possible. This directs all that vigor back into the body of the bush… so it can bloom magnificently after all.

It's The Lawn, Silly

As my colleague Andrew over at land8lounge reports, New Mexico is finally discovering the benefits of grasscycling. For some anecdotal support: I've been using a mulching mower for about 10 years at my home, and have only needed to supplement with fertilizer three times in that period (and have never had to contend with weeds). As for watering, I recommend the guidelines provided by UC Davis; if you need help determining your irrigation system's application rates, ask a landscape contractor who works in your area.

Baby, It's Hot Outside

Even as East Bay MUD proposes its first water-rationing measure in two decades, this week temperatures are expected to soar toward the century mark.

For your garden, this means get a head start (i.e., now) on keeping your plants hydrated. If you're irrigating with a spray system, see whether your controller can be programmed to repeat cycles — so that rather than watering once for ten minutes, which may deliver more water than the soil can absorb at once — your system waters each zone once for five minutes, then repeats the cycle for another five — so Zone A is absorbing while Zone B is receiving. If you're not sure how much water your plants should be getting, get to know your local Master Gardener; you can also extrapolate some good information from publications developed for commercial growers.

If you're irrigating with a low-flow (drip) system, you will want to increase the length of each cycle and/or add a "syringe" cycle in the middle of the day, effectively giving the plants a drink when their transpiration rates are highest.

You'll also want to make sure all that precious water stays in the soil, where the plants can actually get it, rather than evaporating into thin air. The most effective way to do this is with a generous layer of mulch. Most often we think of mulch as fir bark, which is ground to various consistencies (or shredded into "gorilla hair").

However, there's more than one way to mulch: compost is wonderful, adding nutrients to the soil even as it holds water in; and even pea gravel is effective (although pricey and doesn't decompose like organic matter). Some municipalities even give away free compost to residents. The key with mulch is to apply it generously (I prefer a depth of least 3 inches) and regularly. Remember, organic matter like bark and compost break down over time; so plan to reapply an inch or so at least a couple of times a year.

There are plenty of other considerations in creating "water-wise" gardens. The California Water Service has some good resources, including a list of drought-resistant plants; if you've got good tips for getting your garden through the heat, please let me know!