Recent cold temperatures may have damaged plants

Early Saturday morning I saw water that dripped from the ends of hoses lying on the ground. The water had formed icicles at the ends of the hoses, and temperatures were not freezing during the night.

Water remaining in drip lines exposed to wind was frozen as late as 7 a.m. Water couldn’t flow through them. But drip lines and hoses in the sun had thawed by 8 a.m., and water could flow.

Temperatures in the valley are supposed to dip into freezing or near-freezing territory soon. Low temperatures (but not necessarily freezing) in combination with wind will freeze water in hoses, drip lines, puddles and buckets. Plants exposed to wind may have cold temperature damage without experiencing freezing temperatures.

Some early peaches, apples and plums have already produced flowers, while others have not yet budged. In warm locations, they are further along than in colder locations.

Plums, plum relatives and citrus that are now flowering or have finished flowering may lose their fruit this season due to this cold weather. Some of you may not have a crop of Meyer lemon or Flavor Supreme pluot this year because of wind and late-spring cold temperatures. Others will. That’s the power and mystery of microclimates.

There are parts of the valley — microclimates — that never experienced any freezing temperatures this past winter. They still have tomato plants with tomatoes on them. If they don’t freeze, these plants and fruit will be fine.

The most sensitive parts of all plants to cold and freezing weather are flowers and fruit. Some flowering fruit trees are more sensitive to cold temperatures than others. All parts of tomato plants are sensitive. Freezing temperatures will damage tomato fruit, so harvest and bring them inside, even if they are still green.

If you put out tomato plants early, protect them with hot caps or a light blanket during the night. Clear plastic will work if it is secured to the soil and elevated. Place wooden stakes slightly taller than the tomatoes so a blanket or plastic doesn’t crush or touch the leaves.

Secure the edges so that cold air doesn’t get under the covering or blow it away.

Q: Will the fruit from a Last Chance peach tree be tasty in Zone 10, or should I pull it?

A: Last Chance is called “last chance” because it is an extremely late peach variety. The tree will grow fine and produce fruit in the desert. I’m sure of that. But I don’t know about the quality of the fruit. I have never grown Last Chance peach in the Mojave Desert, but I understand it can have a slight puckery, astringent taste when it is ripe.

If you like the fruit, keep it. You might get peaches the first or second year you put it in the ground, depending on the variety. I consider Last Chance peach more of a novelty fruit because it produces so late.

I like peaches that produce fruit early — up to mid-season in the desert to avoid pest problems and reduce anticipation. For me mentally, peach season ends around the first part of August, and apple season begins in September. People stop thinking about peaches in late summer and early fall and begin thinking of apples.

So my favorites usually produce in late May through July. Two notable exceptions are the Indian Free and Indian Blood peaches, which produce fruit with lots of unique appeal when fully ripened.

Q: I found a Meyer lemon at a store in California that looked much different than my Meyer lemon; it was smaller, darker orange and seemed sweeter to me. Is this Meyer lemon different from mine?

A: There are differences between fruit grown in one geographic location versus another geographic location. Sometimes we call these location differences “agroclimatic regions.”

Agroclimatic regions include differences in weather but also differences in soils. All these differences evoke changes in fruit quality, reflected in the quality attributes of the fruit. How the plant is managed or manipulated also creates changes in fruit quality.

We see these agroclimatic differences in vegetables and ornamental plants as well. Sometimes these differences are good, and sometimes they are not. We don’t know until we grow these plants in different locations.

Fruit grown in the Mojave Desert does not have the same quality attributes as fruit grown in nondesert areas. There are many reasons for differences in sweetness, color and sugar content in fruit.

Sweetness or sugar content can be masked by the amount of acidity the fruit has. Fruit grown in the desert typically has high sugar content and lower acidity, so some desert-grown fruit may taste bland compared to fruit grown in nondesert climates. Other fruit might be better.

Differences in fruit quality can be attributed to plant differences, agroclimatic regions and how the fruit is managed on the tree or after it is picked. Differences in fruit quality can come from the variety or plant selection, graftage, fruit maturity, climate and weather, plant nutrition, age of the tree or how much fruit is grown on the tree.

Try fertilizing the trees with a good citrus fertilizer or compost. Change the amount of water the tree gets and try harvesting the fruit later or earlier. Minimize the length of time the fruit is kept in storage once it is picked and off the tree. Prolonged storage can reduce sugar content.

Q: When shopping for fruit trees, I noticed both dwarf and miniature trees available, which confused me. What is the difference between a dwarf and a miniature variety?

A: The difference between the two is a difference in genetics (miniature) versus how the tree was propagated or grafted (dwarf). Miniature fruit trees are regarded as genetically different or independent from other varieties.

The terms “miniature” and “dwarf” are sometimes used interchangeably in the nursery trade for marketing purposes. This causes a lot of confusion for the consumer. But they are different from each other.

Miniature fruit trees (sometimes called genetic dwarf in the nursery trade) are not manipulated to be smaller. Their smallness is in their genetics. They were born that way. Miniature fruit trees do not have to be grafted to make them smaller, but sometimes they are grafted for other reasons. Examples of genetic dwarf apple trees are the varieties Apple Babe and Garden Delicious. Genetic dwarf peaches include Bonanza and El Dorado.

Dwarf fruit trees are made dwarf by attaching them to roots that cause the tree to become smaller. Dwarf fruit trees must be grafted to another tree so that they become smaller. Dwarf fruit trees are small because they are forced to be small through graftage.

By grafting an apple tree to another tree that doesn’t get as large, the apple tree will never grow large. It stays small — a dwarfed form of the same tree.

Fruit from dwarf fruit trees has the same taste and size as the normal-sized tree. But the tree itself remains smaller — a dwarf version of the same tree. There are dwarf forms of Red Delicious, Fuji, Granny Smith, Gala and all other apple varieties. These are all grafted to a dwarfing rootstock.

Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.