Heat-stressed Plants in Las Vegas

Some plants like it hot.  Some really, really don’t.

It’s funny what a little perspective can provide. In May, we’re horrified at that first 100° day. By August, we’re positively thrilled that it’s “only going to hit a hundred!” Heck, that’s jacket weather after we’ve endured a few weeks of 110° days and 90° nights, right?

Fortunately, most of us have air conditioning, shade and water anytime the heat starts to take its toll. Unfortunately for many of our plants, they have access to none of those things. They’re stuck out there in the blazing sun planted in rock and up against hot block walls that reflect the heat back on them for hours at a stretch. Their systems are forced to go into overdrive just to stay alive when temperatures soar and don’t let up, even at night.

Heat-stressed cape honeysuckle (Tecoma capensis)

On top of that, June was especially rough this year. We hit 115° early on and it seemed like the sun just would not let up for a month solid. As a result, we’re seeing trees and shrubs throughout Las Vegas showing their stress in a myriad of ugly ways; from scorched and wilting leaves to bare branches and scalded trunks, our green friends are making their suffering known and begging for some relief. Even plants that can normally withstand our heat are starting to crack.

The good news is that there are ways we can help them make it through the summer heat without adding a lot of stress to our own lives.

Get rid of the rock.  First and foremost, remember that the reflected heat coming off decorative rock is just awful. It can straight up cook soft leaf tissue, particularly on plants that aren’t well-suited to the extreme temperatures of our climate. Pull that decorative rock away from your non-desert plants as much as possible, by at least a couple of feet (and more if you can swing it). Replace it with organic mulch at about a 2” depth to provide a respite from reflected heat and help conserve moisture in the soil. Over time, the mulch will start to break down and introduce organic matter into the soil, something our basically barren soil could desperately use, by the way.

Block the sun. Another strategy for shielding your plants from the effects of the sun is to provide it with shade, especially from the afternoon sun. Tree wrap will defend a trunk against scalding in the summer months. For smaller plants, use a piece of burlap or shade cloth on the west side to offer immediate protection from the most intense heat of the day. Bear in mind that hot Vegas summers aren’t going anywhere though, so it’s probably best to invest in a long-term solution. Plant a larger, more heat-tolerant shrub a few feet away to eventually lend shade to its neighbor and also offer more visual appeal than a seasonal piece of burlap.

Golden dyssodia (Thymophylla pentachaeta)

Reconsider your plant choices. Finally, take a good long look at your garden and consider whether it might be time to switch out some of those tender plants that thrive in Iowa with trees and shrubs that love the Mojave instead.

There are plenty of beautiful desert natives and introduced species to choose from, making this a great opportunity to create room for plants that won’t bat an eye when 115° comes around.  Less work for you, less stress on your plants and a more beautiful landscape in the long run? That’s a winning proposal all the way around!

 

Desert Gardening Book Recommendations

Successful landscaping in the Southwest requires a different set of techniques than used by gardeners in most of the country.  Whether you’re new to the desert southwest, or you’re looking for some fresh gardening ideas, every gardener’s favorite non-gardening hobby is reading about gardening. Here is a collection of desert gardening books we recommend.

A Desert Gardener’s Companion by Kim Nelson

Master Gardener Kim Nelson provides a wealth of information in an easy-to-use seasonal format, covering what to do week-by-week in desert climates.

Nevada Gardener’s Guide by Linn Mills

This book contains easy-to-use advice on the top landscape plant choices.   It also recommends specific varieties, and provides advice on how to plant, how to grow and how to care for the best plants.

Month by Month Gardening in the Deserts of Nevada by Mary Irish

The Month-By-Month series is the perfect companion to take the guesswork out of gardening. With this book, you’ll know what to do each month to have gardening success all year.

Desert Gardening for Beginners: How to Grow Vegetables, Flowers and Herbs in an Arid Climate by Cathy Cromell, Linda A. Guy, and Lucy K. Bradley

Plain and simply packaged, this book does not have gorgeous illustrations or lush photographs, but the information contained within is excellent. From choosing a site to ways to improve soil structure, all the basics that gardeners need for this region are covered. The authors do offer a few suggestions on selecting plant varieties for the desert as well as an appendix devoted to growing calendars for vegetables, fruits, and herbs.

Plants For Dry Climates: How To Select, Grow, And Enjoy by Mary Rose Duffield

Plants for Dry Climates comprises both good landscape design and essential cultural information for nearly 450 plants. It gives readers all the information they need to plan a complete landscape that includes both mini-oasis features as well as arid-landscape plantings.

Sunset Western Garden Book

What plants to grow, how to nurture them, and where they do the very best, it’s all here. The most recent edition of Sunset includes more than 8,000 plant selections for western states. While not all plants in this book are suitable for the desert, this book is a great place to get ideas and understand plant requirements.

Desert Landscaping for Beginners: Tips and Techniques for Success in an Arid Climatby Arizona Master Gardener Press

Desert Landscaping for Beginners contains the latest research-based information from the University of Arizona, written in user-friendly language. Topics covered include selecting and transplanting trees and shrubs, watering desert landscapes, pruning, plant problems and pests, cacti and succulents, wildflowers, roses, citrus, lawns, and the magic of desert plants.

Trichocereus hybrid Flying Saucer blossom

Trichocereus hybrid ‘Flying Saucer’ blossom

Related Images:

Norm’s Caesalpinia Chit Chat: A Primer on the Birds of Paradise

Caesalpinia pulcherrima (Red Bird of Paradise)

Caesalpinia pulcherrima (Red Bird of Paradise)

It’s wintertime in the desert, and even with our relatively mild climate, not all plants respond well to a cold season planting. So, what not to plant this time of year? The first plant that comes to my mind is the summer-time favorite, Red Bird of Paradise (Caesalpinia pulcherrima).

Native to the West Indies, Central and South America, the Red Bird of Paradise is a well-adapted for our hot climate and poor soils. This tropical-looking plant produces large, colorful clusters of orange-red flowers from summer until the first frost, and boasts lush, green, fern-like foliage. Red Bird of Paradise adds superb showy color and a tropical flare to the garden.

It has been my experience that Red Bird of Paradise only takes off well if planted in warm

Caesalpinia pulcherrima (Red Bird of Paradise)

Caesalpinia pulcherrima (Red Bird of Paradise)

weather, so we limit planting them from May through September. If requested by a customer, we inform them of what we know in regards to time of year of planting and let them decide, but really advocate only planting them when nighttime temperatures are above 60°F. Red Bird of Paradise does go dormant in the wintertime, but makes a colorful comeback in late spring. The amazing flower show makes it well worth tolerating its cold weather downtime.

Caesalpinia mexicana (Mexican Bird of Paradise)

Caesalpinia mexicana (Mexican Bird of Paradise)

Unlike the Red Bird of Paradise, its cousin the Mexican Bird of Paradise (Caesalpinia mexicana) has a longer planting season, ranging from early spring to mid-fall. Because it does have the potential for cold damage, and younger plants die in cold more readily than more established specimens, I do not recommend planting the Mexican Bird of Paradise from October to mid-February. C. Mexicana does well in the Vegas valley, and only freezes back in the coldest of years. It will remain evergreen in warmer part of the valley, but will shed foliage when frost occurs. If it does not receive cold damage, it can grow into a small tree of about 8-10′ in height and spread.

Caesalpinia mexicana (Mexican Bird of Paradise)

Caesalpinia mexicana (Mexican Bird of Paradise)

Mexican Bird of Paradise is especially striking in the warmer months when its dark green, fern-like foliage provides a backdrop for the bright yellow flower spikes erupting from the tips of its woody branches. Speaking of erupting, the Mexican Bird of Paradise has a very interesting way of spreading seed! After flowering, the plant forms pea-like seed pods. As the pods mature and dry, the two sides begin to twist, but in directions opposite one another; each side holds the other in check. The tension increases over time until it reaches a point where it can’t hold it anymore, and then, pop! –the pod pops open with a loud snapping sound and scatters the seeds a great distance, often 20 feet or more. Though C. mexicana does look similar to C. pulcherrima, it can be differentiated by flower color and by the size of the individual leaflets of C. mexicana being much larger than those of C. pulcherrima.

Though in the same genus (Caesalpinia) as the Mexican and Red Birds of Paradise, the Yellow Bird of Paradise (Caesalpinia gilliesii) seems to be much more challenged here, especially long-term. The flowers are particularly showy, with a combination of yellow petals and red stamens. If requested by a client, I inform them that it tends to get borers, and suffers from discoloration and die-back of stem tissue, as well as sporadic die-back of random portions of the plant. Over the years, this plant has seemed quite unreliable to me, and thus – no thank you!

Not the Bird of Paradise plants you were thinking of? The other Bird of Paradise plants that are totally different and unrelated to the Caesalpinia are the Birds of Paradise in the Strelitzia genus. Planted on occasion in the Vegas valley, Tropical Birds of Paradise (S. reginae, and S. nicolai) have large, thick, deep green leaves and a springtime blossom that resembles the head of a bird. Tropical Birds of Paradise need lots of water, prefer rich organic soils, and require protection from cold. As you can probably guess, they usually don’t do well in Southern Nevada, except for the rare moist, protected microclimate. Of the two, I’ve only seen the smaller one, S. reginae, survive in an outdoor planting.

Remember, plant the right plant in the right place – and it sure helps if you’re planting it at the right time of year. Happy digging to you!

 

Norm’s Plant Protection Advice for Freezing Temperatures in Southern Nevada

With the threat of cold this coming weekend, some plants could be damaged…you may want to protect them.  This can be achieved in several different ways.  

  • Pile wood chip mulch over a plant.  This can be held in place by a nursery planting container that has had the bottom cut off, thus creating a tube.  Other materials can be used in place of wood chips.
  • Use a thermal blanket or sheet to cover plants.  These can be purchased relatively cheaply at nurseries and hardware stores.  Pin to the ground using large rocks, or better yet, use landscape fabric pins.
  • Use old-style incandescent-bulb Christmas lights.  This is especially useful on trees.  They radiate some heat, usually enough to make a significant difference in reducing damage and increasing survivability.

Both the wood chips and thermal blankets work by keeping “heat” from the ground on the plants…our soils never freeze, so keeping that warmer air around the plant can make a huge difference.  This is one of the benefits of leaving leaf “litter” (think of it as “leaf mulch”) at the base of plants like Lantana or Aloe.

Cold spells where temps drop below freezing are part of our normal weather patterns.  It is when temps drop down to the mid-20’s or below that I start to worry.  The longer it stays cold, and the less the day warms up following each cold night can make a big difference.  Temps are projected to drop into the mid-20’s and rise only into the low-40’s for 3 or 4 days, so damage could occur.

Among the plants you might want to protect are:

  • Aloes
  • San Pedro cactus
  • Saguaro
  • Smaller (<10″ diam) Golden Barrel cactus
  • Rusellia equisitiformis (Coral Fountain)
  • Ruellia sp.
  • Some citrus (Myer’s Lemon should be fine)
  • Cold sensitive species of Agave
  • Many small species of succulents
  • Mother-in-law’s tongue (Sansevaria sp.)
  • Young (less than 1-2″ trunk diameter) cold sensitive trees such as:
  • Skyflower (Duranta erecta)
  • Acacia sp.
  • Texas Olive (Cordia boissieri)

Generally speaking, the central and east parts of the valley stay a little warmer, while the north, west and south perimeters get colder.  Also, plants protected by enclosure in a courtyard or up next to a building receive some protection from cold winds.

Joshua Tree (Yucca brevifolia)

Norm’s Garden: Bearded Iris!

This is one of the reasons I love gardening so…along with the challenges come such unexpected and beautiful rewards. I planted these Bearded Iris about a year ago, forgot about them and either forgot or never knew what color flower to expect. Then along comes spring…kinda like Mother Nature on strong coffee, gettin’ stuff DONE!…and I glance over to see this amazing blue flower gracing my garden.

Iris are fun plants. There are over 200 named varieties, and the word “Iris” comes from Greek, meaning “rainbow”. They don’t seem to take much care, and bigger or more beautiful flowers are hard to find. Rhizomes (the “bulb” part of the plant) should be planted with the roots down and the tip up, just below soil surface or barely poking above. Avoid air pockets when planting, by placing a small mound of soil in the little planting hole you’ve created and spreading the roots over the pile. If you plant more than one (Iris looks great in groups of 3 or more), orient the fans (leaf-groupings) away from each other. In clayey soil plant them a bit high, create a little hill of sandy soil mixed with a little of your clay, or both…they like good drainage. Well-decomposed organic matter mixed into the soil will be helpful as well. Plant new rhizomes or divide existing ones in fall (September-November). They like full sun in most climates, but seem to do better here with intermittent, filtered or afternoon shade. Keep them fairly moist, but if soils stay wet they’ll rot.

Like all of gardening, expect some success and some failure. Of the 5 groupings of Iris I’ve planted, two have taken off and flowered, one produces leaves but hasn’t yet given me flowers, and two have died off. One of the ones that died was a variety named “Immortal”. Such irony! 🙂

Spectacular Surprise from Norm’s Adventures! Arctomecon californica (Bear-Paw Poppy)

On a bike ride out Lake Mead Blvd, past the highest point in the road and starting down the slope to Lake Mead, I stopped to turn around and head back home. I took a few minutes to catch my breath, and climbed a little hill right beside the road. To my astonishment I found a population of 20 of the endangered Bear-Paw Poppies in bloom. They have such beautiful rosettes of leaves, covered in fine hairs to help reduce water-loss in this dry environment. What a special surprise and delight!

Arctomecon californica (Bear-Paw Poppy)

Arctomecon californica (Bear-Paw Poppy)

These little guys are frequently referred to as “bear poppies” and “bear-paw poppies”, because of the characteristic form of the leaves. Arctomecon is a genus of the poppy family Papaveraceae. The three species are said to come about only in the western part of the Mojave Desert of North America. All species are known to be uncommon.

Reference: http://en.wikipedia.org/wiki/Arctomecon

Steve’s Underutilized Trees for Small Yards: Foresteria pubescens (Desert olive)

Forestiera pubescens

Forestiera pubescens by Stan Shebs

Foresteria pubescens; Photo TexasAMU

Foresteria pubescens; Photo TexasA MU

Foresteria pubescens (Desert olive, New Mexico privet, Stretchberry)

This tree has an interesting multi-stem form with green leaves and white bark that is clean and smooth like ivory!

  • Deciduous Perennial with brilliant yellow fall color
  • Yellow blooms provide wonderful spring color around St. Patrick’s Day
  • Attracts birds for shelter and provides food source from the blue toned fruit
  • Enjoys full sun to part shade

It is a suitable substitute for Ligustrum species (Privets) because it’s native to the area and thrives, while Privets are likely to suffer at best.

 

Reference links to check out:
http://aggie-horticulture.tamu.edu/ornamentals/nativeshrubs/forestierapubescen.htm

http://commons.wikimedia.org/wiki/Category:Forestiera_pubescens

Eye-popping cacti from Norm’s Adventures! Mammillaria tetrancistra

I’m blessed to live near Frenchman’s Mountain (aka Sunrise Mtn) and often hike the canyons and slopes with my 3 dogs. It’s a rough, rocky, nearly soil-less mountain, but I’m continuously amazed by the desert life that thrives in such a seemingly inhospitable place. These two little cacti, Mammalaria tetrancistra, are about the size of golf balls. I bent to pet my dog and when I did they sure caught my eye. Talk about eye-popping! 🙂

They are commonly referred to as fishhook cactus, or corkseed cactus.

According to cactigiud.com, the genus Mammillaria is one of the largest of the cactus family, with nearly 200 recognized species. 

http://cactiguide.com/cactus/?genus=Mammillaria

http://cactiguide.com/cactus/?genus=Mammillaria&species=tetrancistra

http://plants.usda.gov/java/profile?symbol=MATE4

Steve’s Underutilized Trees for Small Yards: Pinus monophylla (The Single-leaf Pinion)

 
 

 

Pinus monophylla

Steve's Pinus monophylla

Pinus monophylla (Single-leaf Pinion)

The appearance of this tree has been described as “rustic”. It’s hue compliments many types of landscapes.

 

 

Pinus monophylla (The Single-leaf Pinion) Photo Credit: Dcrjsr wikimedia.org

Pinus monophylla (The Single-leaf Pinion) Photo Credit: Dcrjsr wikimedia.org