Sacramento Digs Gardening: Mystery fruit looks like fuzzy navels

Notice the three-part leaves on this citrus tree. They are a clue to its identity. (Photo courtesy Allen Pierleoni)

Citrus rootstock sprouts a trifoliate orange tree

“What’s growing over my fence?”

That’s a common question from many gardeners, one that I ask myself sometimes, too.

In the case of fruit, it comes with a corollary: “Can I eat it?”

Such is the case of this mystery fruit, spotted by a loyal reader in Fair Oaks. He pondered whether he was going to get some bonus citrus – or should cut the branches back.

“The skin is slightly velvety, the plant is growing next to a grapefruit tree. Unusual leaves, no?” he wrote in a note with his photo of what looked like fuzzy navels.

All three observations were clues to the mystery fruit’s identity – plus one more. Look out for those great big thorns.

The fruit is a trifoliate orange ( Citrus trifoliata ), also known as Japanese bitter orange or Chinese bitter orange. And it sprouted from the rootstock of the grapefruit tree.

Allowed to grow and thrive, the trifoliate orange is forming its own tree – and could crowd out the grapefruit grafted on its roots.

Trifoliate orange – named for those three-part leaves – is among the most cold-hardy citrus. So, it’s often used as rootstock to give tender grapefruit and other citrus a little more cold tolerance (especially in Northern California).

The fruit is covered with soft down. Usually packed with seeds, it eventually ripens to yellow and looks like a small orange but with skin that feels like a peach.

As for taste, it lives up to its bitter nickname.

My advice: Get out the pruning shears.

GENERAL GARDENING

An article about gardening.

Keywords:

garden mystery citrus gardening Sacramento Fair Oaks backyard produce rootstock home orchard

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Garden Checklist for week of May 19

Temperatures will be a bit higher than normal in the afternoons this week. Take care of chores early in the day – then enjoy the afternoon. It’s time to smell the roses.

* Plant, plant, plant! It’s prime planting season in the Sacramento area. If you haven’t already, it’s time to set out those tomato transplants along with peppers and eggplants. Pinch off any flowers on new transplants to make them concentrate on establishing roots instead of setting premature fruit.

* Direct-seed melons, cucumbers, summer squash, corn, radishes, pumpkins and annual herbs such as basil.

* Harvest cabbage, lettuce, peas and green onions.

* In the flower garden, direct-seed sunflowers, cosmos, salvia, zinnias, marigolds, celosia and asters.

* Plant dahlia tubers. Other perennials to set out include verbena, coreopsis, coneflower and astilbe.

* Transplant petunias, marigolds and perennial flowers such as astilbe, columbine, coneflowers, coreopsis, dahlias, rudbeckia and verbena.

* Keep an eye out for slugs, snails, earwigs and aphids that want to dine on tender new growth.

* Feed summer bloomers with a balanced fertilizer.

* For continued bloom, cut off spent flowers on roses as well as other flowering plants.

* Don’t forget to water. Seedlings need moisture. Deep watering will help build strong roots and healthy plants.

* Add mulch to the garden to help keep that precious water from evaporating. Mulch also cuts down on weeds. But don’t let it mound around the stems or trunks of trees or shrubs. Leave about a 6-inch to 1-foot circle to avoid crown rot or other problems.

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