78°F
weather icon Partly Cloudy

Oleander should bloom next summer if moderately pruned

Q: If I prune my old oleanders this fall, will they bloom this coming spring?

A: It depends on how they were pruned and the type of fertilizers applied. Oleanders flower on new growth.

If oleanders are cut to the ground, they first shift their growth to replace leaves and stems that were lost. This is so they collect sunlight for future growth first. In doing so, they replace what was lost before they begin flowering. Producing flowers and seed takes a lot of energy.

Depending on the amount of growth after pruning, they may or may not flower the following year, but they will flower in year two and onward until they are pruned again.

If they are cut back moderately, they will probably flower immediately after new growth appears in the early summer, a few weeks after pruning. There may be a slight delay in flowering, depending on how much of the plant was removed during pruning.

Flowering might be delayed by adding high-nitrogen fertilizers. Making lots of nitrogen available to plants encourages leaf and stem growth first, which delays flowering. Applying reasonable amounts of high-nitrogen fertilizers should not reduce flowering, but when it is applied in combination with severe pruning, it might.

Two approaches used when pruning shrubs is renewal pruning and rejuvenation pruning. Renewal pruning leaves a substantial number of smaller stems remaining after pruning. Only a few larger stems are cut back to the ground.

Use rejuvenation pruning if a tangled mess of growth cannot be easily pruned or there is substantial winter damage. This technique removes all growth to a few inches off the ground. Replacement growth occurs from the remaining stubs left after pruning. Rejuvenation pruning causes the biggest delay in flowering.

Q: I see resorts with gorgeous masses of jasmine, and in many places, they are pruned into low mounds for borders. How do I avoid having the woody, exposed leggy stems showing? Will the plant regenerate itself if I simply prune it all the way to the base? What time of year to do that would work?

A: Star jasmine performs best as a vine, rather than a groundcover or shrub, but it can be used in a variety of ways if given enough room to grow and carefully managed.

The picture of your star jasmine shows it planted a few inches from the brick or concrete pavers. Star jasmine is a medium-sized plant that can grow 2 feet tall and 10 feet wide if left to sprawl.

This means plant spacing should be 5 feet apart to totally cover an area. It should be planted about 5 feet from pavers, not a few inches.

Light pruning can be done anytime, but the best time to prune to optimize flowering is after they finish flowering in late June or July. Pruning then gives the plant a chance to rebuild itself for the next flowering cycle, which should begin in late spring.

Star jasmine can be cut back very hard so that 4 to 6 inches is sticking out of the ground, and it will regrow into a plant full of new growth and flowers. Pruning it as a vine is different. After pruning, apply a light fertilizer application (a rose or tomato fertilizer will work) and water it in.

Q: Is it too late to treat my shrubs for grubs this season? I’ve lost several Indian hawthorn shrubs and several agaves to them during the summer. What is the best time and way to apply?

A: Most information circulating on the internet tells us that grubs are immature forms of specific beetles, usually June beetles. Here grubs might range from scarab beetles (June bug) to snout beetles (weevils) to dung beetles and even flies and moths.

All these different kinds of insects have different life cycles which produce grubs at different times of the year — some at multiple times per year. Many times, we call these types of grubs “white grubs” when they aren’t.

The best time to eliminate them is when they first begin feeding on plant roots as baby grubs. This would be midspring for these types of grubs.

To get good control, the grub should be present and just started feeding. Organic control measures like bacteria and nematodes are quite specific to the type of grub, or it can apply to all the grubs, as it does for some insecticides.

In your specific case, the Indian hawthorn probably has grubs from a type of June beetle, and the agave grub is probably from a weevil or snout beetle. The Indian hawthorn grubs might be controlled with an organic application of milky spores (Scotts GrubEx) in late March or April.

Control the grubs in the agave with an insecticide poured over the top of it so that it runs inside the crotch of the leaves. Apply it to the soil twice: once in April and once in May.

Q: Our subdivision is disgruntled with our current landscape company, as we have 30 bad lawns out of 68. People living here since 2000 say it is the worst. Do you know any companies with a good reputation?

A: This type of question is sent to me quite often and a common complaint from HOAs. The company you privately mentioned to me, generally, has a good reputation. I know areas of town it is servicing, and I have heard no complaints.

Large landscape maintenance companies send crews on specific routes. These crews have supervisors. Maybe it’s a supervisory problem, rather than a company problem. Call the company and initiate a discussion about the problems and see if these can be rectified before moving to a new company.

Q: I have a 3- to 4-year-old crape myrtle that had a lot of flowers this summer. Now the leaves are dark green on the top part but beige or brown on the bottom part. It almost looks like the leaves are burned. The watering habit hasn’t changed. Do you know what the problem would be?

A: That description fits a water shortage to the top of the tree. This could be from not enough irrigation water applied; collapsing soils that suffocate roots and cause them to die slowly; watering too frequently, which also causes roots to die slowly; and damage to the tree trunk, which causes drought and damage to the leaves. All these problems cause leaves to turn brown along the edges.

Follow the KISS principle. Check the tree trunk for physical damage. Borers can cause this damage as well as people. If this is the cause, reduce the size of the treetop by eliminating entire limbs that are not necessary. Reducing the canopy reduces the tree’s need for water.

As trees get bigger, they need more water. Water required by this tree after four years will increase to about 15 to 20 gallons each time you water. If the water is on for one hour, then four or five drip emitters are needed that deliver 4 gallons each hour so the tree gets 16 to 20 gallons each time the tree receives water.

Place emitters 2 feet apart under the tree’s canopy and water at least half the area under its canopy. Give the tree at least a one-day rest when it receives no water at all during the hottest months. Give it more rest days when it is cooler.

Rock on top of the soil can, after about four years, cause this kind of problem. Plants like crape myrtle that are originally from wetter climates and different soils may have a tough time in our soils without some soil amendments.

Soil amendments used at planting time run out of steam in about four years. In other words, they are gone. Rocks covering the soil surface do nothing to replenish the depleted organics.

If the soil around it is covered in rock, rake it back about 5 feet. Then cover the soil first with about 1 inch of compost (about 2 to 3 cubic feet), water it in thoroughly and finally cover this with wood chips 3 to 4 inches deep.

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.

Don't miss the big stories. Like us on Facebook.
Entertainment Videos
Heavier traffic expected from EDC festival attendees
Electric Daisy Carnival attendees began to vacate the Las Vegas Motor Speedway starting before 5 a.m., the majority heading south on Interstate 15.
What it's like to skip the lines and fly by helicopter to EDC
What it's like to skip the lines and fly by helicopter to EDC. (Janna Karel Las Vegas Review-Journal)
DJ Steve Aoki visits Las Vegas comic book store
DJ Steve Aoki visits Torpedo Comics in Las Vegas Friday, May 17, 2019, for a signing for his new comic book series "Neon Future." (K.M. Cannon/Las Vegas Review-Journal) @KMCannonPhoto
Las Vegas Smith & Wollensky opens at The Venetian
After 18 years, the Smith & Wollensky location on Las Vegas’ south Strip closed in 2017, to be re-born two years later with a rib-cutting — instead of a ribbon-cutting — in The Grand Canal Shoppes at The Venetian. (Heidi Knapp Rinella/Review-Journal)
Colin Cantwell, Creator Of Iconic Star Wars Ships Visits Vegas
Colin Cantwell, who created and designed such "Star Wars" ships as the X-Wing fighter, and Death Star, met fans at Rogue Toys in Las Vegas today. (Mat Luschek / Review-Journal)
Beauty & Essex in Las Vegas makes an EDC Wonder Wheel
In honor of the Electric Daisy Carnival, Beauty & Essex at The Cosmopolitan of Las Vegas makes its Wonder Wheel party-worthy. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Giada talks Vegas Uncork’d
Giada De Laurentiis talks during Aperitivo Hour, a Vegas Uncork'd event, at her Caesars Palace restaurant, Pronto, May 10, 2019. (Al Mancini/Las Vegas Review-Journal)
Scenes from Vegas Uncork’d 2019 on the Las Vegas Strip
The 13th edition of Vegas Uncork’d by Bon Appetit brought four days of food, wine, celebrity chefs and parties to town, May 9-12. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Three ingredients Gordon Ramsay can’t live without
Bon Appetit's Andy Baraghani interviews the "Hell's Kitchen" chef during a Vegas Uncork'd event at Caesars Palace, May 11, 2019. (Al Mancini/Las Vegas Review-Journal)
Vegas Uncork’d launches wiith bubbles and a blade
Dozens of chefs representing some of the Strip’s top restaurants gathered Thursday at The Cosmopolitan of Las Vegas to launch the 2019 edition of Vegas Uncork’d by Bon Appetit. (Al Mancini/Las Vegas Review-Journal)
Bunky the Clown at the clown convention
Bob "Bunky the Clown" Gretton talks about his life as a clown and the Clown Convention which was in Las Vegas at Texas Station this week. (Mat Luschek / Review-Journal)
Frying soft-shell crab at Lola’s in Las Vegas
At Lola’s: A Louisiana Kitchen in Las Vegas, soft-shell crab is breaded and fried and served either as an appetizer, po’boy or platter. Heidi Knapp Rinella/Review-Journal
The Stove in Henderson makes Pecan Pie Pancakes
At The Stove in Henderson, chef/partner Antonio Nunez stacks buttermilk pancakes with pecans and dulce de leche and tops them pie crust crumbs. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Vinnie Paul remembered at Count's Vamp'd
The late rocker's favorite table at one of his favorite clubs in Las Vegas. (Jason Bracelin/Las Vegas Review-Journal)
4DX movie experience at Red Rock
4DX movie experience during a demo reel at Red Rock. (Christopher Lawrence/Las Vegas Review-Journal)
What To Do On May The 4th
There are plenty of events going on May the 4th this year around Las Vegas. Celebrate Star Wars and Comic Book Day all at once. The Rogue Toys, the 501st, Rebel Legion and Millennium Fandom Bar are all hosting fun events to help celebrate your geek-dom. (Mat Luschek / Review-Journal)
Las Vegas Water Sports Introduces New Attraction At Lake Las Vegas
Las Vegas Water Sports will debut its new aqua park attraction at Lake Las Vegas Days this weekend. (Mat Luschek / Review-Journal)
Making the Space Invader at Greene St. Kitchen in Las Vegas
Lysa Huerta, pastry cook at Greene St. Kitchen at the Palms in Las Vegas, starts with angel food cake, Fruity Pebbles ice cream and strawberry sorbet to create a space creature engulfed in flashing lights and swirling mists. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Las Vegas Pools
The M, Park MGM and NoMad are just a few great pools in Las Vegas. (Mat Luschek/Las Vegas Review-Journal)
Jose Andres explains Iberico pork
(Al Mancini/Las Vega Review-Journal)
Inside Life is Beautiful
Craig Asher Nyman explains how Life is Beautiful festival is booked and talks about this year's line-up. (Jason Bracelin/Las Vegas Review-Journal)
Tattoo'd America Pops Up In Vegas
Tattoo'd America, a new pop-up attraction on the Linq Promenade, had their grand opening Friday. The attraction is dedicate to the culture of tattoos. (Mat Luschek / Review-Journal)
Jose Andres gets key to the Strip
Chef Jose Andres was presented with a Key to the Las Vegas Strip and a proclamation declaring April 26 Jose Andres Day in Clark County by County Commissioner Tick Segerblom on Friday. The ceremony took place at his restaurant Bazaar Meat in the SLS Las Vegas. (Al Mancini/Las Vegas Review-Journal)
Sadelle’s in Las Vegas makes a grilled cheese with an inverted bagel
Michael Vargas, executive sous chef at Sadelle’s at Bellagio in Las Vegas, inverts an everything bagel and grills it with Swiss, cheddar and Muenster cheeses to make the Inverted Bagel Grilled Cheese. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Learn how to make China Poblano's Salt Air Margarita
Learn how to make China Poblano's Salt Air Margarita (Janna Karel Las Vegas Review-Journal)
Tattoo'd America invites you to have fun and take pictures
Kassandra Lopez at Tattoo'd America invites you to have fun and take pictures. (Janna Karel/Las Vegas Review-Journal)
Prime rib is carved tableside at Lawry’s The Prime Rib in Las Vegas
Dave Simmons, executive chef of Lawry’s The Prime in Las Vegas, which plans special cuts for National Prime Rib Day, demonstrates the restaurant’s service from rolling tableside carving carts. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Making gluten-free pizza at Good Pie in Las Vegas
Good Pie owner/pizzaiola Vincent Rotolo makes his gluten-free pizza.
Rockabilly fans enjoy Las Vegas weather poolside
Viva Las Vegas Rockabilly Weekender runs Thursday, April 18th through Sunday, April 21st with a huge car show on Saturday featuring The Reverend Horton Heat, The Delta Bombers and The Coasters. (Michael Quine/Las Vegas Review-Journal)
Brownie sundae at VegeNation in Las Vegas is completely vegan
Donald Lemperle, chef/owner of VegeNation in Las Vegas and nearby Henderson, NV, makes his sundae with ice cream made with coconut and almond milks, a brownie made with coconut flour and oil and organic sugar and cacao, and fresh fruit. (Heidi Knapp Rinella/Las Vegas Review-Journal)
THE LATEST
Spray grapevines to control pests

Grapeleaf skeletonizer and grape flea beetle were found in the orchard during the last couple of days. These two pests damage grape leaves but few other plants.

Removing dead fronds doesn’t affect health of sago

Q: The top ring of sago palmfronds died after I transplanted it but remain on the plant. I left this brown ring of fronds around the crown of the plant and it looks like new growth coming from the center is OK. Should I trim off the dead fronds without disturbing the crown or just let them fall off?

Yellow leaves not necessarily caused by fertilizer

Q: I see many times where you’ve said fruit trees only need feeding in the spring. However, without periodic applications of nitrogen, my 3-year-old peach tree leaves become yellow. Could there something going on I should investigate?

Waxleaf privet should have more than one drip emitter

Q: I purchased a few waxleaf privet plants in February. They were planted in my yard using drip irrigation with one drip emitter per plant for about one month now. I am starting to see some black markings and yellowing on the leaves. I also think there may be some root rot, but I am unsure.

Removing excess fruit allows remaining fruit to grow larger

If you have fruit trees, the next big tree management activity you are facing is fruit thinning or removing excessive amounts of fruit so that the remaining fruit gets larger. Peaches, nectarines, plums, apples and pears must have excessive fruit removed if you want larger fruit. Do this as soon as the fruit reaches the size of your thumbnail.

Proper pruning, thinning, irrigation increases fruit size

Q: Peaches from my dwarf peach tree were very small again last year. This is the third year the fruit developed into a small size. We fertilize them twice a year with vegetable spikes and our in-ground system fertilizer system has Dr. Benson’s Natural Mix added five times per year. Any suggestions?

Grape varieties grown in hot dry climates do best here

Q: I am from San Miguel Community Garden, a nonprofit garden located near the North Las Vegas Airport. We are considering adding more grape plants to the garden. We have Flaming Red and Thompson grapes. You said you have grown many different varieties in the Las Vegas Valley, and I was wondering if you would share with me other varieties that were successful for you so we can explore them as well.