Garden Detective

Garden detective: Early heat means bad year for cherries

I talked to a master gardener (recently) about my fruit trees. Everything has just been falling off my trees. The cherry tree was in full bloom with lots of bees this year; same thing with the grapefruit. Then, everything on the cherry tree fell off; nothing took. Now, the grapefruit is doing the same. Do we have a major problem?

– Lee Moser, Sacramento

According to farm adviser Chuck Ingels of the UC Cooperative Extension, “The cherry crop statewide is a disaster due to very warm weather during bloom. Cherry prices will be very high and cherry growers will have a rough year. Also, for the first time, North Coast fruit growers are feeling the effects of low winter chill.”

The cherry bust also will be felt in the Sacramento area by home gardeners, he added.

“This is an exceptionally bad year for fruit set in cherries and some other crops throughout the state,” Ingels said. “Most cherry growers will lose about 80 percent or more of their crops this year, which is devastating.”

The issue wasn’t drought, but heat.

“The problem is that it was very warm during bloom,” Ingels explained. “You wouldn’t think that would be a problem, but apparently the pollen tube stops growing or aborts when temperatures are above about 70 to 75 degrees. Add on top of that the fact that, although we had lots of ‘chill hours’ – hours in winter below 45 degrees – the ‘chill portions’ were low.

“Chill portions are a more accurate way to calculate winter chill; they cancel chill hours when winter daytime temperatures are high, which occurred through much of the winter. Chill hours reflect what the trees experience.”

So don’t expect many cherries this spring.

As for the grapefruit, there’s hope. Its fruit drop may have been normal.

“Regarding the citrus, there is a normal fruit drop every spring, since the tree can’t support all the fruit that would be produced from all those flowers,” Ingels said. “Hopefully, there will be enough left for a good crop. There could also be some weather effect on the grapefruit tree, but give it some time to see how much fruit make it through.”

This mystery flower just opened (in April). Can you please identify it?

– John Reagan, Sacramento

That’s a spraxia. Sometimes called Harlequin Flower, this pretty bi- or tri-color bulb flowers freely throughout mid-spring. It naturalizes easily and makes a good cut flower for spring bouquets. Once established, it will keep popping up for years.

Spraxia is native to South Africa, but is found throughout California. It escaped cultivation and became an introduced species.