Growing blueberries in Southern California

Growing blueberries in Southern California

My wife is from Oregon, where blueberries can really grow. On our visits up there I’ve seen what healthy blueberry bushes are supposed to look like. Mine don’t look like those. But my blueberries do look better and produce more now than they did when I started trying them out about seven years back. I have learned a couple things about growing blueberries in Southern California that I think are worth sharing.

Soil pH

As you’ll read any time you read anything about blueberries, they need soil with a low pH, around 5 according to this University of California publication. We don’t have such soil in Southern California. In the two different gardens I’ve tested my unadulterated soil, they have registered about 7. (I tested with a Luster Leaf Rapitest pH Soil Tester.)

So the easiest, surest, smartest way around that is to grow your blueberries in a pot with a purchased soil mix that is already in its preferred pH range. I’ve got a friend who grows wonderful blueberries in a half wine-barrel.

I, on the other hand, have always gone the hard way and grown them in the ground and tried to alter the pH of the good old earth around the root zone of my blueberry plants. Some say this isn’t even possible. I’ve heard many people say blueberries won’t do well long-term in Southern California in the ground. My oldest plant has been in the ground for seven years and it looks as good today as it ever has. No doubt though, I’ve done numerous things to try to get the soil right. That’s a constant battle.

When I planted them I mixed peat moss into the planting hole. I’ve continuously added acidic items to the soil surface: oak leaves, pine needles, coffee grounds, and lots of extra rainwater (which has a lower pH than the imported tap water of Southern California — about 5.6 compared to about 8.4 for my particular water district).

Yet my plants still began to show chlorosis (leaves with yellowing between the veins). It’s said to be due to a deficiency of iron when the soil’s high pH doesn’t allow for the root’s intake of iron. So I bought a box of soil sulfur, but nothing much improved. Then I bought a box of aluminum sulfate and incorporated some of it into the soil.

sulfur for blueberries aluminum sulfate for blueberries

It was unusual for me to buy boxes of sulfur and aluminum sulfate, and I was uncomfortable applying them to my soil. I try to be careful about, and aware of, what I add to my soil. In fact, these blueberry plants are the only things in my yard that I’ve added anything to besides compost and wood chips. But my blueberries were obviously struggling and my decision was between giving up on growing blueberries or adding these chemicals. I decided to try the sulfur and then the aluminum sulfate mostly as an experiment to see if they worked.

Because I’ve done so many things, I can’t say for sure what the effect of each addition has been. But my suspicion is that aluminum sulfate has had a bigger and quicker effect than anything else. After I added some for the first time last year (to lower pH), my plants showed almost immediate appreciation with less chlorosis.

It could’ve been coincidence though. Not sure. Another friend, who lives not far from me in Ramona, San Diego County and has had a handful of blueberry bushes in the ground in her yard for about fifteen years — yes, fifteen years — gets loads of production from her plants and says that she has only added sulfur to the soil.

Related to soil pH, see this presentation by University of California farm advisor Ben Faber on soil pH management if growing blueberries in the ground. And note that Faber mentions that if soil is high in organic matter — for instance, if you’ve added a lot of compost, wood chips, oak leaves, pine needles, and coffee grounds for many years — then blueberry plants in that soil will tolerate a pH somewhat higher than 5.5.

My plan now is to continue adding acidic organic matter to the soil surface and add no more sulfur or aluminum sulfate unless, possibly, my plants show that this is inadequate.

Sunshine Blue blueberry plant in full sun

Sun or shade

A planting location in full sun has given the most berries for me. I’ve grown plants in sunny and shady spots — here in my current yard twenty miles from the ocean, as well as when I lived two miles from the ocean — and while the plant foliage looks healthier in some shade, the plant produces more berries in the sun. I’m growing all but one of my blueberries in full sun now, here in the foothills of Southern California where the sun is more intense compared to the beach.

blueberry plant in partial shade

My only blueberry in afternoon shade. Its foliage is impeccable but berries are fewer.

Varieties

I’ve grown a handful of varieties, but one has far outshined the others. I’ve grown Misty, O’Neal, Jewel, Jubilee, Pink Lemonade, and Sunshine Blue, but it is Sunshine Blue that has done better for me than all of the others.

Recipe for success

If you’re trying blueberries for the first time, I’d recommend the simpler route of growing them in a large container rather than in the ground as I do. Growing in a container is more expensive, but it’s certain to be successful if you buy a big container like a half wine-barrel, buy some acidic potting soil to fill it (such as one that says it’s for azaleas and camellias). Put a Sunshine Blue plant plus one or two other varieties in there. Place the plants in full sun and make sure to water often — blueberries don’t like to dry out, in my experience, and plants in pots dry out faster than plants in the ground.

Why plant more than just one variety? It’s said that blueberries produce more when grown with multiple varieties together. I don’t know how true this is because I’ve always grown multiple varieties together. But since different varieties ripen at slightly different times and taste a little different, you might as well plant multiple varieties together.

Doing this, you’re sure to have fresh blueberries for the picking from about now (late April — we just started picking a few days ago) into June.

As for me, I’ll continue to do my best with plants in the ground. Hey — mine aren’t as pretty and productive as those in Oregon’s Willamette Valley, but they’re a lot tastier than anything I can buy in a plastic clamshell at the grocery store.

Want some deeper reading about growing blueberries in Southern California? See the University of California’s Blueberry page.

Grapevine on eave to shade house

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This is the native grape of our area, Vitis girdiana, and I planted it two winters ago. Grapes grow like grass fires! The first year I tied it up a string that I hung from the fascia board. This year I tied it along a wire that runs parallel to the fascia board, fastened to eye screws and held taut by a turnbuckle.

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That’s the end of its training. Now I’ll only have to prune it up each winter so the winter sun can hit our windows and warm the house, and so the view of the mountains is preserved.

A grapevine does this job of summer shade far better than other plants I’ve tried. Beans burn out before the summer is over, tomatoes require planting, training, and pruning every year, and passion fruit isn’t deciduous. Also, believe it or not, I’ve only given this grapevine a little water every couple weeks through the summer. Looks like I’ve found the winner.

The view each morning from inside the house looking out is now so much softer than the straight summer sun; it’s of glowing grape leaves.

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Propagating grapes with cuttings

Last winter, my friend Frank cut some pieces off his grapevines and gave them to me. I stuck them in the ground and they grew into new grapevines. Could it be that easy?

'Blueberry' grape rooted last year, pruned back and flushing out again this year

‘Blueberry’ grape rooted last year, pruned back and flushing out again this year

This winter, I cut some pieces off those new grapevines and stuck them in the ground. They’re now pushing out small green leaves. It is that easy.

You read of people incorporating complex and expensive techniques and materials to propagate grapes, as well as other plants. They grow them in pots filled with certain percentages of perlite, they buy hormones that are said to induce rooting, etc. But I did little other than just stuck them in the dirt. And I had about 90% success.

The vines that Frank cut as well as the new vines that I just cut were bare and dormant. This was done in mid-January.

The cuttings were all 10-16 inches long, and each had a minimum of four buds. They were as thick as a pencil up to the thickness of a man’s thumb. Almost all of the cuttings I stuck in the ground last year rooted out, but the two that didn’t were only pencil thickness.

My process was to take a shovel and make a vertical slit in the dirt about eight inches deep and then stick the cutting, which just looks like a brown stick, into the slit. I sunk each one so that only two or three buds were above ground, and therefore at least two buds were below ground. (I transplanted last year’s cuttings at the same time I was sticking in this year’s cuttings, and I noticed that they had all rooted out precisely from the points where the buds were underground, most prolifically from the deepest bud.)

I poured some water into the slits and then pressed the soil closed around each stick. From that point on I aimed to keep the soil around the sticks moist, merely moist — not dry and not soggy. I poked around every week or so and added water if necessary. Last year’s cuttings were surrounded by tomato plants by the spring, so I just let them be watered on the same soaker hose with the same schedule that watered the tomatoes.

The ground where I put the cuttings last year was in full sun and this year I put some in partial shade. It hasn’t seemed to make a difference.

Incidentally, Frank gave me some cuttings off branches of a couple of his pomegranate and fig trees last year too, and I stuck them in the ground right beside the grape cuttings and they all rooted out just the same. Thanks, Frank.