Correcting Lemon Mistakes Through Proper Pruning When Young

Q. Your Xtremehorticulture blog is an awesome source of information! I live in Phoenix and question why my ‘Lisbon’ lemon tree is failing after two years. It flowers in the early spring as it should, and produces fruit, albeit, its fruit is nasty and dry. The canopy is about 10% of what it should be, and I suspect sunburn has been choking the plant. I think the tree is a goner and thinking of removing it.

'Lisbon' lemon tree grown in Las Vegas and sun damage to the leaves.

A. Yes, I think your tree may be sunburned. Give it a chance still. At two years of age, you might be able to nurse it back to health if you follow some easy directions.

You live in the northern part of the Sonoran Desert. Las Vegas is in the eastern side of the Mojave Desert. All citrus including ‘Lisbon’ lemon are subtropical; this means the tree, unlike ‘Myers’ lemon, doesn’t survive freezing temperatures very long. And in your case our very strong desert sunlight. As the canopy increases in shade and size, giving more shade to the fruit and the tree itself, the fruit will improve. Guaranteed. Don’t let the fruit overripen before you pick it. That’s a no-no.

This citrus tree was limbed up too soon and the trunk may develop sunburn in hot locations.

You might be able to get away “limbing it up” like in the seaside and Mediterranean area of Portugal, where ‘Lisbon’ lemon probably originated, but it won’t work in the desert Southwest. Leave the tree shrub-like the first few years until it gets established and then slowly limb it up, making sure the trunk and limbs stay shaded, as it gets older.

Citrus with a full canopy but exposed fruit still developed sunburn in Arizona.

Make sure the soil has been amended at the time of planting. This is a subtropical fruit tree and requires more organic matter in the soil than we have in most of our desert soils. I would not surround this tree with rock or rock mulch on the surface of the soil. Instead, use a layer of 3 to 4 inches of wood chips keeping the wood chips away from the trunk the first few years of its life. As the wood chips on the soil surface decompose or rot in the presence of water, it will slowly add “organics” back to the soil. Rock doesn’t do that.

The last thing to consider is planting the tree on the north or east side of your landscape, or at least 3 or 4 feet away from a hot west facing or South facing wall. It may or may not need it but it can help the tree. All fruit trees need about eight hours of sunlight each day, but subtropical trees can do without the 120°F heat common in Phoenix. If they are in good health, they will withstand the desert heat.

A Black Fig is a ... Black Fig

Q. A friend gave my husband some fig fruits. This friend said the fig tree is just so full of fruits enough for all his friends and birds. They're so sweet, very deep (almost black) purple, and small; about an inch around. Can you identify this fig please?

Unknown "black fig" from homeowner. 

A. There are many different black or dark purple fig fruit varieties. All the fig varieties do well in Las Vegas if there given enough water. I need more to go on than just the size and the color of the fruit. Varieties of black or purple figs include ‘Black Mission’, ‘Blackjack’, ‘LSU Purple’, ‘Violet de Bordeaux’. Celeste and others. From your description my guess would be ‘Black Mission’ but it’s just a guess.

'Celeste' fig ripe.

Next March try rooting about ten stem cuttings from the tree if you want to preserve the fruit. You will have to label in “Unknown” unless you can discover the variety. Use a rooting hormone like Hormex #16 when you do it just to improve your chances of success.

These are grape cuttings but it gives you the approximate size of stem cuttings. Dip the cut ends in rooting hormone to improve your chances of success.

Birds can be a big problem since this fruit is ready to harvest the same day birds like them. Unlike some other fruit, figs are what we call “non-climacteric” which means they must be left on the tree until they are ripe and ready to be harvested. Other non-climacteric fruit include grapes, apples, pomegranates, and a few others.

Bird pecked fig fruit.

Desert Problems with Star Jasmine

Q. I have a Jasmine plant and it was flowering but not it’s not and not looking good. What is your call on it?

A. Most times when people say they have a “Jasmine” plant they mean star jasmine. Star jasmine is not a true Jasmine, but the fragrance can be delectable which is true of most in that plant family.

Star Jasmine, a vine or groundcover from warm areas of China, may develop iron chlorosis when grown in a rock mulch.

            Star jasmine comes originally from China so it will like improved soils and dislike rock mulch. Whenever a plant comes from a non-desert area then try to plant it on the East side of your landscape. This area receives shade in the afternoon and is more hospitable to plants that are not from the desert. It can be grown as a groundcover or as a vine, but it must be tied to a trellis to get it to perform as a vine.

Star jasmine grown near a door or window will provide a great fragrance to a home. Star jasmine needs an organic soil with woodchips covering it to look its best.

            Most star jasmine in poor health are surrounded with rock mulch. If your star jasmine is in poor health, then surround it with wood chip mulch rather than rock mulch. When it’s planted, make sure the soil is amended with compost. Dig the hole three times wider than the container or its root system and add the amended soil to this planting hole. If it’s a 5 gallon or larger plant, then stake it. The wood stake that comes with many local nursery plants is adequate for smaller plants as long as it is pounded into the solid soil beneath it and retied with nursery tape. Most plants require only one season of staking and then it’s removed.

            The only way to re-green yellow leaves is by spraying it with an iron solution. Early next spring, apply any iron chelate to the soil. For difficult yellow plants to “green-up”, use the EDDHA iron chelate applied to the soil in early spring.

Weed Control Around Saguaro

Q. I have a 25-foot Saguaro cactus with at least 7 arms in my Palm Springs landscape. My gardener just put Roundup around it to control weeds. We had this done a few years ago, and since then the Saguaro leans dramatically.  I didn't want him to put it there.

Saguaro cactus in a Sonoran landscape in Parker, Az.

A. I wouldn’t spray Roundup close to it unless you protect the Saguaro. It says on the label to protect anything green because it is a general killer. It was developed originally is a grass killer but it will kill nearly everything if you apply the right concentration.

The base of Saguaro will develop tough brown "bark" areas as it gets older. Even though it might be there, protect the base with cardboard when spraying systemic weed killers like Roundup.

            An older Saguaro like yours should be developing some woody brown areas towards the base as parts of it remain green but that’s not enough. Anything you don’t want damaged or killed, protect it. An easy way to do that is a cardboard barrier to protect the Saguaro. After you’re finished spraying you can either remove it or just use it as a shield when you’re spraying Roundup close to it.

Peaches Produce Fruit at Different Times With Different Flavors, Aroma and Flesh Color

Q. Several years ago at the University orchard on Horse Drive you gave us a list of five different peach trees to plant, each ripening at different times. We’ve enjoyed peaches from May through September ever since. Thanks.

'Earlitreat' peaches on May 24, 2005, at the University orchard in North Las Vegas. Other good early peaches include 'FlordaPrince'. 'FlordaKing', and 'Earligrande'.

A. I prefer to plant entire fruit trees, rather than a single tree with several varieties (think “fruit cocktail” trees). that ripen at different times of the year for many different reasons. Let’s talk about one of them.

Peaches like this Early Elberta ('July' or 'Kim') make the next round along with 'June Pride', and 'Snow Beauty'.

Generally, the varieties of fruit trees that flower earliest produce the earliest fruit. In our climate peach varieties start flowering the first week of February and other later producing varieties of peach may start flowering as late as the as the end of April. Later flowering varieties frequently produce fruit later as well.

Dont forget the flat peaches like 'Donut' and 'Galaxy'. They produce fruit also around July.

As examples, the peach variety named ‘Earlitreat’ begins flowering the first week of February. Other early producing peaches like ‘FlordaPrince’ and ‘FlordaKing’ start flowering about a week after ‘Earlitreat’.  If there is a frost while the flowers are open, think early spring through early summer, it produces less fruit or maybe no fruit at all! These varieties of peaches will produce fruit (if frost permits) in mid to late May until early June.

Peach varieties like 'Indian Blood' may be worth the October wait due to its very special aroma and flesh color.

The variety of peach called ‘Red Baron’ produces fruit around July but doesn’t begin flowering nearly a whole month later than ‘Earlitreat’; early March! By selecting varieties that flower early or later usually will affect when the fruit is produced. The missing information are the varieties that taste the best! Each peach variety is different, performs differently in the desert and tastes different.

If a light frost occurs anytime between February 1 and the middle of March (estimated date for our last frost can be as late as March 15!) then we will be guaranteed fruit if we are growing several varieties of peach trees in the same location.