One of the interesting things that you can observe in the garden is a colorful disease that affects roses called rose mosaic. It is caused by viruses that infect roses. 

Rose Mosaic Symptoms

There a number of "mosaic" diseases caused by viruses that affect plants. In general, they cause parts ot the leaf to turn color—usually yellow. To someone with an artful eye, the pattern can sometimes resemble a tile mosaic, but this is highly variable. (See some pics on Google here.)

In roses the symptom is usually angular, splotchy yellowing on the leaves, but sometimes it can take on a pale yellow band on a leaf that zig-zags around. It's not so much the shape of the symptom that alerts you to its presence, but more that in spring the whole plant will have a similar yellow pattern on most of the leaves of the same age and sun exposure.

In roses there are 2 primary viruses that cause mosaic: Rose Necrotic Ringspot Virus and Apple Mosaic Virus. In addition there are many unknown causes and at least another virus that can cause these symptoms. Often there are multiple causes.

Most grafted roses in the Eastern Sierra that are about 20 years or older show mosaic symptoms. I usually see symptoms in spring, but once the weather warms up, the mosaic pattern vanishes. April and May seem to be most pronounced in effect. 

Why do we have this so commonly here? This is a disease that is usually spread through propagation. I suspect most of our roses ultimately came from 1 or 2 wholesale nurseries that had the virus in their stock plants used to bud or graft onto the ubiquitous Dr. Huey rootstock. Today this virus is less common in the trade. Nurseries have means to remove virus from their stock plants through tissue culture, if they so choose.

The virus doesn't do much harm in the landscape other than making early season leaves look weird. It may also reduce vigor and stem length. I don't lose much sleep about it, and there really aren't any control measures if I did! If mosaic bothers you, the best course of action is to remove the plant and start anew. 

For more information: The UC IPM program has a page on rose diseases. This old article (1977) from California Agriculture also has information and some pictures about rose viruses. The Marin county Master Gardeners also have some information on mosaic diseases in general in the garden.

My wife, Mrs. Kunze, is a 2^nd grade teacher at Bishop Union Elementary where she has taught for the past 31 years. She and her next door teacher, Mrs. Kubiak, also teaching second grade, often do class projects together and such was the case as they discussed how to teach the mathematical skill of making a line graph. Their idea involved planting something that would grow, that the kids could measure and graph, and would be fun for them while teaching them multiple skills. After 33 years of being the husband to a 2^nd grade school teacher, it was no surprise that my name was quickly decided upon as someone that could help out on this project.

Finding ways to get my volunteer hours in that did not involve weeding the community garden demonstration plot was an opportunity I appreciated and this presented the chance to show the class not only how to plant a seed, but to also talk about how seeds grow, nutrition, the joy of gardening.

Cost of the presentation was kept to a minimum, I bought 1 cubic foot of potting soil, sixty blue and red 18-ounce Solo cups, and 1 packet of sugar snap peas. I chose the peas as they were easy for second graders handle and plant, and since they have a fairly quick germination time (8-12 days) it helps to keep the kids interested.  Also, they were something that would produce a tasty treat that could be picked and eaten right off the plant when mature. The money spent was paid out of classroom funds raised at the Harvest Hoedown - a fundraiser which is held every fall to enable just these kinds of classroom projects.

I arrived at Elm Street School at 10:30 Monday morning, green Master Gardener apron on, name tag in place and proceeded to the classrooms to prepare for my presentation. Both classes joined together while I spoke to them about whom I was, the Master Gardner Program, how plants grow and the different ways to start them, along with the benefits of eating fresh vegetables right out of your garden. Although I had the official Master Gardner business cards, and said I could help them find online resources, being second graders they did not seem too interested in that part of my presentation. I answered several questions, many of which were actually stories about an individual student's gardening experience and then moved on to the next part of my presentation.

The classes separated and went back to their respective rooms and the process of sending students to meet with me four at a time began.   I enjoyed this part the most as I was able to speak individually to each student, and assist them with planting their seed. After writing their name with a sharpie on the outside of the cup, then punching a hole in the bottom, I would give it to the student to fill with the potting mix then, I would add water and they would pack the soil down. After using their finger, to make a hole in the soil, they would pick and place the seed in the hole, and cover it back up and again, pack it down. From there they would take their cup outside and place it in a tray donated by Bishop Nursery. I would then repeat the process with the next student. It took several hours but by 1:30 that afternoon, all the seeds were planted and set outside.  

Putting their hands in the soil was met with a reaction that ranged from joy to yuck, but mostly joy. Listening to them talk about how some of them did this at home and how much they enjoyed working in their own gardens was fun. I was especially taken back by how many worked in the garden with a grandparent and how close and inspired they felt by doing so. This was something we might all remember when we spend time with our kids or grandkids.  For most of these children, gardening was a joy, but for far too many it was something they had never done.

I am now done with my part of this project unless Mrs. Kunze or Mrs. Kubiak has reason to bring me back. As I said, they are planning on doing a math lesson teaching line graphs that will require keeping track of dates and how much each plant has grown by particular date. For me, I anxiously await, hoping that the seeds will sprout and the kids will find that joy in eventually getting to pick sugar snap peas right off their own bush and enjoy that wonderful delight. I have about 15 extra cups planted just in case some seeds do not sprout but I can use them in my own garden or I'll have sugar snap pea plants for the next MG meeting to give away.

Water-thrifty plants can produce a colorful border

Being a drought-concerned citizen you have ripped out your lush green lawn, so you no longer need to water, mow or fertilize, but you are faced with a large area of bare earth, your topsoil is vanishing into the next county when the wind blows, your earthworms are dead, and if it rains every dormant weed seed springs to life.

You have converted your sprinklers to an ugly spaghetti of drip irrigation tubing and have to decide which water-thrifty  plants to install in order to cover the many square feet of seemingly baron land. So often the ensuing low water use landscaping consists of three clumps of ornamental grass surrounding a lump of rock on a mound, but it is possible to have far more interest and color by selecting appropriate flowering plants, and these are also helpful to pollinating insects?

Which plants to choose? I have seen gardens in the Bay Area where the lawn has been removed and replaced with a mass of roses – perhaps not quite in the spirit of water conservation! Plants native to specific areas should do well if the conditions provided match those in which they naturally grow, but sun-loving plants are not likely to thrive under your neighbor's shade trees, and it is often difficult to match soil conditions. Desert natives have generally adapted to grow, flower and seed when they can take full advantage of any rain that falls, after which they either die or go dormant. This means that much of the summer they will be well past their best, often degenerating into a stand of dead stems.

Below are some plants which have a single taproot or a confined root mass, that can be watered by just one or two emitters, but which have tops that spread to fill up large spaces. While not true desert plants, they manage to look good on low amounts of water, and have long bloom seasons, although since they are dormant for the winter months, other plants, grasses or rocks would be needed to supply interest then.

Nepeta, with a long flowering season.

Aremesia foliage will turn silvery-grey as it matures.

Nepeta racemosa ‘Walker's Low'. This produces a mound of aromatic foliage 2 feet or more across and about 1ft. high. Spikes of lavender blue flowers cover the plant beginning in April, and if the first flush of flowers is sheared off more will be produced throughout the summer. The flowers are irresistible to butterflies and bees and one spring I counted 15 Painted Lady butterflies on one clump.

Oenothera fremontii ‘Shimmer'. Low growing mats of narrow thread-like foliage up to 14” across happily grow in poor, sandy soils and give rise to masses of 1½” clear yellow flowers throughout the summer.

Artemesia ‘Powis Castle'.   This has wonderful, feathery, silver leaves and makes a mound up to 3ft tall and 4ft wide so is a good background plant and space filler. It is tough and looks best if it is cut down every spring in order to get a good flush of new foliage. Spikes of insignificant yellow flowers can be removed for the sake of appearance.

Gaura lindheimeri. Fountains of airy white or pink flowers cover these plants all summer and are a favorite of bees. Some varieties grow up to 4ft high, but most of the commoner garden selections reach 2-3ft, with some being even more compact, reaching only 1ft.. These have deep taproots which are drought tolerant, and a mat of mottled foliage spreading up to 3ft across. Some new cultivars have eye-catching colors and a more compact form.

Mirabilis jalapa. Four O'Clocks. These grow as an annual in the high desert, grow 3'-4' tall and as wide. They grow rapidly and bloom in a variety of colors towards the end of summer. They are frequently perfumed in the evenings. They seed prodigiously.

Perovskia atriplicifolia. Russian Sage with its spikes of long-lasting blue flowers thrives in full sun, and is heat and drought tolerant. It needs plenty of space and reaches a height of about 5' with a spread of 2-3'.

Agastache ‘Desert Sunrise' makes dramatic clumps up to 4' high and 24” wide with generous spikes of flowers in sunset colors throughout the summer. The common name of Hummingbird Mint is self-explanatory.

Centranthus will spread to 3' wide.

Centranthus ruber. This is a weed in much of the west, but given a little water it is hard to beat for a lush appearance and flower production and is a great favorite with insects of all sorts, from butterflies and bees to tarantula hawks! Keep dead flower heads trimmed to prevent production of fluffy dandelion-like seeds. It's not terribly aggressive in Owens Valley but it can spread to neighboring beds with irrigation if you don't deadhead it. 

There are numerous other plants such as the sages and lavenders that give long-lasting and generous displays of flowers with low water usage. Although within each family different species have varying requirements, and different heat and cold tolerances, but with some research it should be possible to find enough plants to make a bare patch come to life using considerably less water than the original lawn.

Sources: www.HighCountryGardens.com

http://www.perennials.com/plants/oenothera-fremontii-shimmer.html

http://www.perennials.com/plants/artemisia-powis-castle.html

If you open up a pest management guide for apple or pears—those books really exist, by the way—the first insect listed is always the dreaded codling moth. These are the creatures responsible for turning an apparent bountiful harvest of fruit into a brown, wormy mess in late summer. Codling moth is the main insect pest that attacks apples and pears in our region.

Codling Moths

After overwintering as larvae, the moths emerge in spring, mate and then proceed to lay eggs on the fruit. These eggs hatch into tiny larvae that eat their way into your fruit, ruining it in the process. Fully grown larvae fall out of the fruit, pupate into adult moths (usually on the ground), and the process repeats. In the Owens Valley, there are usually two generations that we worry about controlling. Their development is mostly driven by temperature.

The first generation of adults usually emerges in April, and egg laying follows in a few weeks. The exact timing varies each year and by location, north or south, in the valley. The second generation lays its eggs over an longer period, but it is usually in July. Most of the complaints of ruined fruit by gardeners are from this second generation.

Damage from Codling Moth Larvae

Because there are at least two generations to be concerned with, it is essential to get control during the first generation so that you have fewer moths to fight later on.

While it's possible to achieve control by just using continual sprays through the season with insecticides, this isn't usually how we deal with this pest since that's wasteful and carries risks. Codling moth is usually controlled through a combination of means.

Commercial codling moth control is a complex topic. There is a great body of peer-reviewed literature on the subject. In the home landscape it really isn't possible to implement a full, successful control program. UC has a simpler set of guidelines for landscapes and gardens here.

The approach I would recommend to is to watch your fruit closely. Ideally you should learn what a codling moth egg looks like and learn to identify it. If you want to control with sprays, egg laying is the only feasible time to apply an insecticide, Organic or otherwise.

Codling Moth Egg

Codling Moth Egg Laid on a Leaf for Scale

Codling moth eggs are tiny and hard to see. They look like tiny translucent pancakes about as big around as a pencil's lead. These are usually laid near the blossom end of the fruit. I find them easier to see in the morning or late afternoon when the sun is low in the sky. They are slightly reflective and having sunlight reflecting on them is a big help.  Check those fruits you can reach easily from the ground for the eggs by turning the fruit and looking around the blossom end. The third week in April is a good time to start looking in our area. Continue this through mid-May. Remember that Bishop is about 1 week behind Lone Pine in timing. Check for eggs again in late June through July. Egg laying is your best shot for applying controls.

If your eyes aren't good, you'll have a hard time knowing when to time sprays by finding eggs, but there are other options. A favorite home control technique of mine is to remove all fruit of the first generation that has a worm. This alone can go a long way in getting control, especially if you're not surrounded by neighbors with wormy fruit.

If you really want to have clean fruit, in June you can bag fruit to protect them from insect attack. Garden supply companies sell bags for this purpose, but you can improvise as well. Have bags on fruit before egg laying commences. Since we have wind issues, you'll need a way to secure the bags onto the fruit. Bagging is a lot of work! Anytime you see fallen or damaged fruit on the tree, you should remove it immediately whether you bag or not.

Unless you are committed to bagging fruit, most homeowners who demand high levels of control will need to spray some product. These vary from biological organisms that kill the target pest as well as naturally or synthetically derived insecticides. Because these products and recommendations change so often, I'll direct you here for current recommendations. (See bottom of that page.)

Codling moth control is definitely a challenge, but you can expect reasonable control with a little effort on your part. Even if you lose some crop each year, you should still have enough to make growing apples and pears worth your while.