Desert Rose Gardening: What to do in May 2016

                                                                                                       By Sharon Radice Moore

Pierre de Ronsard: gardeningexpress.co.uk

Pierre de Ronsard: gardeningexpress.co.uk

 

I grow roses; actually roses, herbs, vegetables and nut grass, because truthfully there are few places I would rather be than in my garden. Only there do I exist in serene symbiosis with the plants, people and wildlife I adore.Nevertheless, as the calendar fades from spring to summer, I know I must hasten to gather the last of my rosebuds for bouquets, potpourri, teas and oils before the end of May as summer will soon beckon at my garden gate.

 

Labors of Love for May:

Traditionally, in the desert rose garden, May is the month to begin transitioning from spring to summer with the primary focus(s) on PREPARATION and PROTECTION. Given the early onset of summer temperatures this year (again), this is vital if not critical to begin this transition in May.

Tools: Better Homes and Garden

Tools: Better Homes and Garden

Soon your last bloom cycle of the season will disappear into memory. Flower production will diminish; bloom size shrinks; color fades, leaves scorch and canes darken. This can be startling, yet it is only unique to growing roses in the desert.

FERTILIZING: May is the last month before summer that I feed/fertilize my roses. Any later and frail new growth cannot withstand the intense heat and may not survive. Some gardeners feed half strength throughout the summer months going full strength again with their end of summer clean-up and light pruning in late September or early October. However, I do often feed half strength SUPERthrive to those struggling with summers sizzle.

WATER is the key to your rose garden surviving the summer and living to bloom again in the fall. This is best done early in the morning or after 3:30 p.m. daily. When the temperatures are consistently 85 degrees and above, which I think started in January this year, irrigate twice a day.

Certainly, a controversy still active within the rose community is whether overhead or low-flooding irrigation systems are superior.

Nonetheless, one thing is DEFINITE, an early morning high-powered spraying down of your roses, in addition to their regular watering, is mutually agreed to be beneficial. This removes many pests and the magically reappearing sand no matter how many times you brush, broom or spray it away.

Second only to watering, you must inspect, repair, replace, and adjust sprinklers routinely. Our intense heat can crack even new equipment. The high mineral content in our water can build-up in the heads limiting volume and heavy growth can restrict output and re-direct spray.

Drip irrigation systems are especially vulnerable to disrepair; watch them closely even if depressing to visit the rose garden deep into the summer season.

PESTS: Check for pests often. Most commonly found in the desert are spider mites and aphid. Yes, we also suffer with powdery mildew, leafcutter bees, and the dreaded hoplia beetle; however, spider mites are my particular nemesis. Indeed, they are not spiders at all, even so, if killing or maiming my roses, I want them gone without reverence to ancestry.

Spider Mite Webbing: Gail Trimble -

Spider Mite Webbing: Gail Trimble 

These unwelcome guests, the two-spotted spider mite or Tetranychus urticae, called by its friends, is the one most common to roses. They prefer hot and dry conditions, dust (sand anyone) and adore heat reflected from pavement and walls. Spider mites loathe cold and wet climates; nevertheless, their populations can explode when warm and humid conditions prevail.

Mostly likely, you will first notice their visit by observing a yellow speckling on the lower leaves of  your plant where they begin their journey upward after arriving on the winds.

Because they are so tiny and dragging a microscope into the garden unseemly, tap the suspected foliage over a white sheet of paper and if small dots appear, congratulations, garden guests arrived and dinner (your roses) is already being served.

Next, turn the leaf over, and you will find a fine silken web devoid of any pattern or design used to cover themselves from predators and hold discarded mite skins, dead mites, mite eggs and poop. They are lousy housekeepers.

As they multiple the entire plant can be covered, which is why early detection and action is critical. Spider mites feed by sucking the sap from your plant and can defoliate the whole bush in record time. One summer I was away for a week, and they consumed my tomato garden of six plants.

A light infestation can be controlled by expelling them with a high-powered water blast from a hose at the first sighting for three consecutive days to stop the infestation before it starts, early morning is best, paying special attention to the underside of the leaves as well as the top. Spider mites turn away from wet places, but will return faithfully without diligence at their door.

The good news is their life cycle is as short as two weeks, so a good spraying off a couple of times a week, after the initial three-day  elimination period, is beneficial for their continued demise and for many other unwelcome garden guests as well.

Soaps, oils and miticides are available, if your infestation is advanced. Still, using the same product repeatedly can provoke a resistance and may will kill mite predators AND bees, so inquire of your nurseryman and read for yourself before you indulge.

Finally, (at last) the most vulnerable plants for spider mites to infest are minis, potted plants and Rugosas, because they appear to enjoy the texture of the leaves.

Aphid Infestation: University of Florida

Aphid Infestation: University of Florida

Aphids can be eliminated as can hoplia beetles, by picking them off with your hands; I suggest using gloves.

Conversely, why not take a bit of help from nature and invest in a large supply of ladybugs, aphid’s natural predator, and set them free in your garden. Ladybugs are sometimes available at garden centers and always by mail order.

Peculiarly, the hoplia beetle and leafcutter bees have two things in common. Both are seasonal, and neither can be completely eliminated. Patience and time’s passage are your only allies with these destructive pests.

 

The hoplia beetle, also identified as the grapevine hoplia flies into our gardens from March to May. They feed on rose petals, predominately light-colored ones and other plants leaving tiny holes in a lacey pattern behind as their signature.

The preferred method of managing their infestation, if light, is to pick them off and discard them in a bucket of soapy water. One research source I studied also suggested leaving containers of soapy water among your plants. This is purported to fascinate hoplia’s, causing them to drown in the containers. No, I do not believe in Santa either; and I digress.

Hoplia Beetle: Blado Villegas

Hoplia Beetle: Blado Villegas

 

Unfortunately, hoplia’s often tuck themselves deep into the folds of the petals making them difficult to find. Do not be fooled by this behavior; they are not shy. Hoplia’s freely mate on host plants, and bury their eggs in soil where they overwinter, thrive on a diet of plant roots and live to destroy more blossoms the following spring. Again, spraying is not recommended as chemicals can harm bees and is only effective upon contact.

 

Leafcutter bees, placing aside the damage they do, are one of the most curious creatures in my rose garden.

Leafcutter Bee Damage: gardenersworld.com

Leafcutter Bee Damage: gardenersworld.com

Leafcutter Bee: telegraph.co.uk

Leafcutter Bee: telegraph.co.uk

These unique visitants are present, usually beginning in early spring, when distinctive semicircular cuts about ¾ of an inch in diameter appear on the edges of your rose leaves. Unlike most pests, leafcutter bees do not use these cut pieces for food.

Instead, they use them to construct their nest cells, often in large rose canes where they previously created tunnels in the pith. The female bee endows each leaf-lined cell with a mixture of nectar and pollen, lays an egg and seals the cell closed. A finished nest may contain over a dozen such cells forming a tube 4 to 8 inches long. Young bees develop in their cells remaining there until they emerge the following season. One adult female can lay in her two-month life cycle, up to 35 to 40 eggs!

Insecticides are ineffective prevention from this pest. Instead, seal exposed rose canes with white glue or products sold for this purpose after pruning to prevent “tunneling.”

Even if you do not see any pests, washing down your foliage twice a week or more is a simple preventive practice, and an invigorating start to your day. If you have roses under attack, a regular serving (once a week) of SUPERthrive, can assist in restoring them to wellness by strengthening their core constitution.

 MAINTENANCE: When deadheading, and cleaning your roses, remember protecting their canes from sunburn is one of your topmost priorities for the summer months. This means leaving unsightly dry, scorched leaves on your roses to protect their canes.  I will never get used to this part of desert gardening. Painfully, I can attest to its need. My first year in the Coachella Valley I confess to murdering several roses by making them “pretty” until they died of cane sun scalding intensified by a lack of mulch.

RESTORE MULCH: (from two to four inches) to both your in ground roses and those in pots. Even if you only do this for the summer, your roses will suffer less heat-stress, return more robustly in the fall, and survive another summer. Even if you do not mulch your entire garden, consider applying mulch in the hottest areas.

Brilliant Pink Iceberg

Brilliant Pink Iceberg: File

 

Pay close attention to potted plants. If they dry out, they may not survive. Grouping pots close together can help them retain moisture as well as using moisture retaining potting soil initially. Furthermore, when adding additional soil due to shrinkage from the heat, do not forget to add some in the bottom too!

 

 

 

 

Photo Credits:

Pierre de Ronsard: gardeningexpress.co.uk

Garden Tools: Home & Garden

Spider Mite Webbing: Gail Trimble Marin Rose Society

Aphid Infestation: University of Florida

Hoplia Beetle: Baldo Villegas

Leafcutter Bee Damage: gardenersworld.com

Leafcutter Bee: telegraph.co.uk

 

Until next time: from my garden to yours,

       Think Rosy Thoughts, Sharon