March 3, 2012
Oh it’s been a long time since I’ve had my hands on a keyboard. When you write a blog, you need to do it more than once, or it isn’t a blog anymore, it’s just something you did once. To get me to sit down behind a computer screen, there’s got to be a pretty powerful trigger event. The recent cold weather has given me that impetus. Yesterday, the 18th of January, our town, La Selva Beach, claimed the county low of 25°. We’re just northwest of Watsonville, a mere ¾ of a mile from the ocean, but it gets surprisingly cold here. I recorded 26° in a spot under the canopy, against a fence (surely not the coldest place) in my grove. The previous week has been cold, as has the entire winter, with frost nearly every morning since early December when we dipped down to a low of 27-28°. The last three days have seen the mercury in my yard fall from 28° on the 16th, to 27° on the 17th down to the low of 26° last night.
I’ve not exactly been hoping for this kind of extreme, but it does give us a chance to observe how some of these experimental avocados fare. That is the question at the crux of this whole exotic avocado project: Can we expect to successfully grow a Sharwil avocado in our yard, or must we resign ourselves to the thin pleasure of merely planting them over and over again? Maybe there’s a mathematical equation describing the waning satisfaction in each successive failed attempt, ebbing to a refusal to try another one. Being the first damaging cold many of these young trees have seen, this is our chance to begin to understand what varieties are going to work for us.
Only spotty data is available on the relative cold hardiness of the avocado varieties we’re trying. Most of it’s from southern Ca., and not very encouraging. Have these varieties even been tried in Santa Cruz County before? If so, the tablets were lost. This is a condition endemic to fruit growing. The various western garden references are but a barest of beginnings. The work of determining the best things to grow is ultimately our own, because everyone’s site is unique and non-uniform, our needs and tastes differ, and lots of good thing have never been tried.
The report offered here won’t apply to everyone’s situation. You might even laugh at the fact that it’s only a single thermometer (not even digital) upon which I base my data, and so can know almost nothing about the actual thermal landscape of my yard. These trees, however, are all planted pretty close together (within about a 75’ radius), subject to more or less (as noted in the table below) the same conditions, so there may be some value in comparing and reporting on the damage sustained by each variety. To the extent your place is like our place, this information may be useful.
|Variety||Desirability of Location||Condition of Tree||Tree Size||Extent of Damage|
|Nabal||Prime-||Fair||Small||5+, 3 below|
|Big Sur #2||Prime||Very Good||Medium||1|
|Big Sur Round||Prime||Very Good||Medium||0+|
|Daily 11||Prime||Good||Very Small||3|
|Bird Avenue||Prime||Poor||Very Small||0+|
|Sir Prize||Prime||Very Good||Large||2|
|Bonny Doon||Prime||Very Good||Large||2|
|Carmen Hass||Fair||Very Good||Large||2|
|Ibis||Poor||New Graft, fresh shoots||Small||5|
|Bears Lime||Prime||Very Good||Small||2|
|Lavender Gem Mandarin||Fair-||Very Good||Medium||2|
0= no apparent physical damage beyond minor discoloration.
1=almost no damage, only a few tender tips
2=minor damage to tender growth on part of the tree.
3=minor damage to tender growth throughout the tree.
4=clusters of leaves burnt, including larger leaves.
5=mature leaves killed and twig tips burnt back a few inches.
Condition of tree rating (pre-freeze):
Poor=yellowish green color, sparse, blotchy leaves, stalled growth.
Fair=greenish color, thin canopy, blotchy leaves, stalled growth. Good=green color, full canopy, some signs of growth.
Very good=dark green color, dense canopy, strong growth.
To the extent you’re growing some of the varieties listed in the table above, this first installment of information may help you gauge whether it’s worth trying some others you know not of. Up here in the avocado outer-reaches, we need to plant the best varieties that have a chance (even if we’re alone in doing so), and we need some luck. We need to be open to all possibilities, but open as well to the facts when they indicate we’re wasting our time: sometimes a tree just needs to be chopped out. This job requires a certain degree of cold brutality, tempered with fair-minded leniency. To not botch too badly this winnowing process we need to tease out some of the various factors influencing a particular trees failure:
Condition of tree is important: Stalled-out, yellow, salt-burned avocado trees are less hardy than healthy ones of the same variety. High nitrogen levels make avocado leaves more cold resistant. A tree that looks blue-green, may slide right through a cold event without damage if it’s between growth phases. With new shoots all over it, the same temperatures may burn it badly, but growth often resumes in what’s survived of those shoots, as soon as things warm up again, leaving you with a bigger, better tree come springtime.
Size really does matter when it comes to avocado cold hardiness. Large canopies hold more residual heat than tiny shoots, insulating the inner parts of the tree. So full bushy trees will take more cold than naked straggly ones. The most vulnerable situation would be the tender shoot from a fresh graft: all soft exposed stem, widely spaced, large succulent leaves. A tree in this condition could be several degrees less cold tolerant than a full, healthy specimen of the same variety.
Position in the grove can spell doom for a tender variety that would succeed in a more favorable spot. The temperature varies all over my yard, depending upon whether it’s a high spot on the south side of a fence, for instance, or behind a structure, shaded at sunrise, on the bottom of the yard where the cold air accumulates. The differing damage levels between the few duplicate trees in my planting indicate, if only weakly, these effects.
Some of the results in the table above are noteworthy, because they’re either extremely good or extremely bad. Starting with the most stunning failure, the hardest hit tree in the yard was the Ibis. This tree was just grafted onto the stump of our former Fuerte tree, in late August. At the lowest point in our avocado line, against a cold air dam in the form of an eight-foot hedge, shaded from the sunrise by the neighbors’ Winnebago, this is unquestionably the worst spot in the grove. The original Ibis mother tree, a 30-foot tall, 50(?) year old chance seedling was discovered last spring in Corralitos. It was loaded with tasty, long-necked, Feb-April ripening Mexicola-type fruit weighing up to one pound each. Growing as it was in a cold part of the county, and displaying Mexican genetic traits, we guessed it would be happier in this bad spot than the Fuerte was. We guessed it would prove itself to be a great new avocado for colder climates. We guessed it was our best chance to rapidly screen our view of that blocky white Winnebago. Maybe we guessed wrong. All tender green shoots and succulent young leaves, our little Ibis had no canopy to speak of, no hardened-off leaves, and everything burnt back to ¼ inch stems.
You might think privately that only an idiot would be grafting avocados outside in late August. Isn’t that inviting failure, waving all that tender new growth at the frosts coming only a couple months away? True, it’s not very smart, but our mid-May graft attempts failed, and the mother tree was being removed. It’s gone, through the chipper now, so we had one last chance. The 5/8 inch main stems look fine, the tree will live, but it inspires empathy. Combination bad position and vulnerable condition will prevent us making any snap judgements on this variety. We’ll wait and see how it does in the future with a full, hardened-off canopy.
Next worst was the Nabal, despite a much more favorable location. This small tree has not grown well, and went into winter with old looking leaves and exposed, sunburned stems in the top of the tree. These mostly turned black, leaving a crown of dead twigs and clusters of full-sized, blackened leaves, while the bottom ¾ of the tree looked only lightly damaged. It seems this is a slightly frost sensitive cultivar made more vulnerable by the poor condition of the top branches. It’s encouraging to see clusters of tiny shoots forming throughout the still-surviving upper parts of this and most of the other damaged trees. Could the burn-back act as a growth stimulus? This is the first time my Nabal has ever shown any enthusiasm.
Next is the Magoon and the Sharwil. They stand 7’ apart in the grove, and appear similarly afflicted, with blackened clusters of leaves from the recent growth flush. The damage is evenly distributed, but superficial in that only the freshest growth appears damaged. The Magoon is notable in that it is actually two trees: our original tree that’s always looked to be near death, and another one we grafted onto a vigorous rootstock and planted a foot away for insurance. The sallow, chlorotic, original tree is not quite as badly damaged as the healthier newer tree. I think it’s supposed to work the other way around, but the trees don’t seem to know that. Both the Sharwil and the healthy Magoon were grafted this March.
It needs to be mentioned that some trees just seem to be smarter about cold weather than others. The Reed, Hellen, Greengold, Bonny Doon, Ettinger, and Lamb to a lesser extent, all managed to restrain themselves from throwing out quantities of early bloom. In contrast, Hass, Gwen, Carmen-Hass, Pinkerton, Queen, Nowells, and Jan Boyce were all sporting open flower clusters which mostly froze off. Particularly disastrous was the nearly complete loss of the Carmen Hass trees’ November-set crop. This tree hardly makes any fruit in the spring, when it’s supposed to, but it starts blooming again in late September. The honey bees are more desperate in the Fall, as they rummage through the clusters like thrift store shoppers, while the Spring bloom they treat as they do my other avocado flowers, with almost complete indifference. (Not to brag, but the Carmen Hass held onto more than 50 fruits last November, and the new crop looked just as good until this freeze.) So, except for the late Fall fruit-setting varieties, an early flower thinning can actually be a good thing. It has been shown to increase fruit set, provided there are enough undamaged flower buds remaining. Still, I prefer the control afforded by a sharp pair of Felcos, and I like it when my avocados bloom late.
The various problem trees mentioned above aroused my maternal instincts. I was disappointed at their shortcomings, but not surprised, as I suspected their weaknesses. I’m optimistic about their futures as I feel most of the fault for their failures lies with us, in their shaky condition and/or their very youngness. Time and attention can cure both, and when these trees have more ballast to them, we’ll better be able to judge their relative hardiness.
Some trees in the grove deserve notice not because they failed us, but because they met the challenge unexpectedly well. The Queen had only minor damage to the tenderest leaves. Greengold was another one I was worried about, but it came through with only a few tiny tips burnt. The Ardith, newly grafted in April, grew to four feet, but pretty whippy and thin. Upper leaves discolored, but only the tiniest tips were singed. Koala, Big Sur Round, Gem and Edranol showed great resistance, boasting only minor reddish brown spotting on otherwise sound leaves. Carmen Hass and Reed were both carrying big crops of well developed fruit, none of which was damaged. The tree most unscathed was the Bird Avenue seedling from Willow Glen. With dense, nutty, Greengold-like flesh, we loved these fruits when Jeffrey Wong of the Santa Clara CRFG shared them, scion-wood, and the story of the tree with us last spring. Grafted in late April, planted out in July, it has looked pretty sickly and hasn’t grown much since. Our Bird Avenue tree still has a weak look to it, a bit yellow, stalled-out and vulnerable looking, but the cold seemed to cause no harm.
I feel as un-entitled to celebrate these seeming successes, as I am reluctant to bemoan the tender trees’ failures. One freeze provides insufficient data to decide anything. A harsher cold snap might kill some things, or require special protective measures, and would certainly provide us with more data. 26° is only a normal season’s low, but it is encouraging, because the trees all seem able to withstand it, and will come through to the spring with blossoms, and fruiting potential intact.
This is the basic test they need to pass. This minimum hardiness is especially necessary for avocados. They’re usually too big to protect before they bear fruit, and they carry their fruit through at least one winter, and up here, often two. I feel more secure knowing I needn’t pray for a string of miracle years if I want a chance to eat a Sharwil or a Queen from my own backyard. Maybe I’m jinxing myself, but these varieties display a durable toughness beneath the tantalizing fantasy. They can tolerate a normal year’s cold at my house. That doesn’t mean they will make me lots of fruit. They may not make any fruit, but hope is alive, and the honeymoon can go on a little longer.
Epicenter Nursery & Fruit, our avocado tree nursery, was born out of frustration at our failure to locate the truly great avocados of the world we’d gotten wind of through the writings of Julie Frink and others. Watery Zutanos, Bland Bacons, delinquent Hasses, bitter little ‘cados, stingey Stewarts, fickle Fuertes are what we as consumers are stuck with, and when someone says they love avocados and are growing all the different types, their list rarely extends beyond these. For twenty years we’ve been exploring the staggering spectrum of flavors in the apple world, out beyond the land of the red and golden delicious, and when we finally cut out that old cypress hedge and made a commitment to living off the fat of our own land in the form of avocados, we knew with near certainty we’d be richly rewarded for looking beyond the workhorse commercial varieties.
Forgive my ingratitude; it’s not avocado snobbery so much as recognizing the practicalities of fruit pedaling. Hass is king of the market for good reasons: It’s delicious (though not the best) and way more adaptable than the also- delicious but tender flowered Fuerte it dethroned. It peels well, it stores and ships well, comes in a convenient and affordable half pound size, and can be harvested over an extremely long (8 months +) season. The clincher however, the trait that won Hass it’s spot atop the avocado world is it’s black (bruise and bump concealing) color that made it look and therefore sell better than the green-skinned competition. So what’s not to love? We do love the Hass avocado, but don’t believe the hype, some of those important marketing traits aren’t traits we, as backyard avocado growers and lovers, care about, or even desire. I don’t care if my fruit is black or not, or roll evenly through sorting machinery, or store for two weeks or six months at 34 degrees. I do, I really do want to grow huge, three-pound avocados (if they’re delicious), even if (maybe especially if) they’re oddly shaped. I will tolerate imperfect peeling, variations in ripening schedules, or countless other quirks and idiosyncrasies that might trouble me if I were selling to Safeway. There’s nothing sacred about the Hass, We are free to embrace a much broader array of attributes in an avocado if the eating quality merits it.
Besides the particularities I don’t need, there are also some things about the Hass I don’t like. Hass is slow. We own a pampered twelve year-old Hass tree that’s made less fruit in its life than our four year- old Reed has. Hass trees are big. Reed, Edranol, Magoon, Sharwil, Pinkerton are smaller and fit in a yard better, pick easier. Flavor is another factor. Hass is not the best. It’s not as rich as a Green Gold (but it’s cold- hardier), or a Sharwil (ditto), or as nutty as a Jan Boyce (but it peels and stores better), or a Reed (Reed does everything better except tolerate freezing temperatures) or a Nabal (but it crops more consistently), or even a Bonny Doon. Hass is not as profound as a Nimlioh, or a Queen or a Daily 11 (weighing in at over two pounds each), or even a Hellen (weighing in at a mere pound and a half). Hass is very good, good enough to become an icon, like the Red Delicious did in the apple world. It has monopolized our conceptions of what an avocado is. It’s prevented a generation or two from even wondering what else is out there.
“What are we missing?” That’s the thought seeping through our minds when first we encountered Julie Frink’s articles in the Fruit Gardener magazine a few years back.
It was the impetus behind our pilgrimages to meet her, buy trees, taste fruit and discover more fully the treasure she is. Her work with the U.C. Irvine avocado germplasm repository has afforded her the rare opportunity to evaluate more than 150 avocado varieties. Her generous power-hitting personality, practical imagination, skill and dedication as a propagator, and opinionated and entertaining writing style have spawned a minor frenzy of avocado interest. We are grateful for her work and her being, she has both inspired and provided for us.
How amazing is the privilege to trial these avocado varieties that have never before been grown in northern California. We get to observe the little quirks that give each variety a sort of fingerprint, that determine whether it’s adapted for growing here or not. Like for instance the fact that the Jan Boyce, perhaps best tasting of all the avocados, seems to flower late here, waiting somehow for the warmer nights of May to bloom and thus succeed in setting fruit readily. Sharwil, reputed to be cold tender, yet there it was a solid clutch of five or six big fruit hanging from that unlikely looking branch grafted to the underside of a friend’s Watsonville Pinkerton tree. The robust, sturdy looking flower stalks on the Hellen last year when it first bloomed, seemed impossible that they would all fall off. It’s probably an exaggeration to say it makes you feel like Christopher Columbus discovering the new world when you grow something really good that’s never been even tried here before, but it’s got us hooked. Care to join us?