Poor blackberry pollination can be traced to spring weather
This Babycakes blackberry, a patio-size plant, produced just a few misshapen
berries this spring. Weather played a large part in the problem. (Photo: Debbie
This berry season, the bees let me down. My usually dependable blackberry plants bore precious few berries. The ones that did develop turned out misshapen. Instead of clusters of berries, the canes were covered with dried-up brown stubs.
I had lots of flowers – beautiful white blooms that usually attract bees with no problem. My blackberries grow near a big bed of roses; bringing pollinators into my backyard has never been a problem.
But this spring was different. In particular, my Babycakes dwarf blackberries fell victim to rollercoaster temperatures. Early April warmth (including 92 degrees on April 8) brought out the first berry blooms. But that was followed by a sudden plunge back into the 50s and frost on April 12. That sudden, unseasonable frost may have snuffed out pollinated blooms.
Once the flowers open, their stamens and pollen stay viable for only a short period (usually three days); they need bees when they need them. Honeybees don’t like wildly fluctuating temperatures. They don’t come out when it’s too cold or too hot, and it was both while those berries needed their help.
So the little pollination that did happen was extremely spotty; my guess, it was self-fertilization, not bees.
Adding to the berry dilemma were heat and drought, especially in June as berries were ripening.
Sacramento set a record for most 100-plus days in June; 11 days hit triple digits including a streak of eight straight. Three June days reached 104. That put heat stress on plants as berries were developing.
Vines already were thirsty. The last six months have been almost bone-dry, and even those notoriously vigorous blackberry roots were subject to dieback. Unless plants got supplemental irrigation, the vines tended to brown and often aborted berry production. (My Babycakes plant has the added challenge of growing in a large pot.)
And it’s not just my poor Babycakes that’s suffering. I’ve seen a similar lack of pollination and vine dieback in blackberries in our local greenbelt.
Fortunately, my vines are already sprouting healthy green growth. It’s time to cut out the old canes with their brown stubble, and move on. Maybe I can get a fall harvest? We’ll see what the bees are doing in August.
For more on blackberries and other caneberries, here are UC cultivation notes: https://www2.ipm.ucanr.edu/agriculture/caneberries/Growth-and-Development/ Also, here's good information from the Sacramento County master gardeners on growing caneberries in our region: https://ucanr.edu/sites/sacmg/files/74193.pdf
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Dig In: Garden Checklist
For week of March 26:
Sacramento can expect another inch of rain from this latest storm. Leave the sprinklers off at least another week. Temps will dip down into the low 30s early in the week, so avoid planting tender seedlings (such as tomatoes). Concentrate on these tasks before or after this week’s rain:
* Fertilize roses, annual flowers and berries as spring growth begins to appear.
* Knock off aphids with a strong blast of water or some bug soap as soon as they appear.
* Pull weeds now! Don’t let them get started. Take a hoe and whack them as soon as they sprout.
* Prepare summer vegetable beds. Spade in compost and other amendments.
* Prune and fertilize spring-flowering shrubs after bloom.
* Feed camellias at the end of their bloom cycle. Pick up browned and fallen flowers to help corral blossom blight.
* Feed citrus trees, which are now in bloom and setting fruit.
To prevent sunburn and borer problems on young trees, paint the exposed portion of the trunk with diluted white latex (water-based) interior paint. Dilute the paint with an equal amount of cold water before application.
* Cut back and fertilize perennial herbs to encourage new growth.
* Seed and renovate the lawn (if you still have one). Feed cool-season grasses such as bent, blue, rye and fescue with a slow-release fertilizer. Check the irrigation system and perform maintenance. Make sure sprinkler heads are turned toward the lawn, not the sidewalk.
* In the vegetable garden, transplant lettuce and kale.
* Seed chard and beets directly into the ground.
* Plant summer bulbs, including gladiolus, tuberous begonias and callas. Also plant dahlia tubers.
* Shop for perennials. Many varieties are available in local nurseries and at plant events. They can be transplanted now while the weather remains relatively cool.
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