BOOM!! We have flowers!   There is an old saying, “April showers bring May flowers.”  If you heard that as a kid you would finish that ditty with, “What do May flowers bring?” – you know the rest. While that is generally true in many areas of North America, here in the Napa area we get rain earlier and we see roses as early as March.  If you are further north it may not be until June or July to get blooms.  Most of Napa is in the USDA Plant Hardiness Zone 9b, which means we do not get as cold as much of the United States this time of year. Therefore, we get flowers sooner. In the last couple of years, we've also received more moisture from increased winter rain and coastal fog.

According to Master Gardener's Rose Cycle, April is when we watch for pests and diseases. We do that by opening up areas of new growth by selective pruning, allowing better circulation of air to the new foliage.

 With the relatively warmer weather and rain in our area, roses do well. However, so does fungus. Fungi are the most common cause of plant disease and black spot is a very common occurrence in our coastal areas. See Photos 1 & 2  below.

 

Photo 2 – Black Spot

Although black spot is caused by a fungus that requires moisture from rain or fog, it is especially prevalent when moisture stays in place for more than seven hours–much like our nice foggy coastal nights and mornings. This also holds true if you hose off aphids in the evening rather than in the morning. Doing the hosing in the evening will not allow the foliage to fully dry before the coolness of the evening sets in. The black spots occur on the upper surface of the leaves and stems, but not underneath the leaf. The spots are small to large with accompanying yellowing of the rest of the leaf.

Black spot can be minimized by pruning your bushes in such a way to allow ample circulation of air that can, in turn, reduce the dampness in the center of the bush and around the congested stems and branches. That is also why we, at the Fuller Park Rose Garden do our winter pruning and early thumb pruning of the lower parts of the canes in February and March. By doing so we encourage openness of those congested areas that will allow air and faster drying times. That task reduces fungal growth later in the Rose Cycle year. There are varieties of roses that are more resistant to black spot than others. When deciding to buy a new rose bush, ask your local nursery which bushes will be best in our area to resist fungus.

If you do not catch the black spot infestation early enough, your action of choice is to pick off leaves and clear away the infested materials that have fallen to the ground around the bush. The ground will harbor spores that can get on your plant again. Spraying your pruning shears and gloved finger tips with a disinfectant between plants will also reduce the exposure to disease infested bushes and those that are not so. You may consider using oil sprays such as neem oil to reduce the occurrence of black spots.

Remember: Toss that plant debris into your city compost bin and NOT your own compost pile. The City of Napa Solid Waste and Recycling Center's equipment produces temperatures high enough to destroy the spores while your backyard pile will not do so.

If you have questions about the Fuller Park Rose Garden and the Master Gardeners (MGs) who maintain that Rose Garden, the MGs are usually in the garden mornings of the first Sunday and third Thursday of each month between 10:00 and noon, weather permitting.

Watch for information about a Summer Rose Pruning course coming May 4^th at our MG Classroom and the hands-on portion on May 9^th  at the Fuller Park Rose Garden. You can also go to our Master Gardner website: napamg.ucanr.edu more details.

Next month we will start our Rose of the Month feature in this blog.

Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143.  Volunteers will get back to you after they research answers to your questions.

Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.

Photo credits:  Bob Niklewicz

I know that this might sound strange to you, but today, March 20^th, the first full day of spring, I was admiring the various types of weeds and wildflowers that are popping up in my garden. It reminds me of the quote, “Weeds are flowers too, once you get to know them.”-A.A.Milne. I was admiring the various colors and types of plants that are popping up in the sun-drenched part of my garden, such as the dead nettle (Lamium purpureum), field marigolds (Calendula arvensis), miner's lettuce (Claytonia perfoliate), musky stork's bill (Erodium moschatum), a species of filaree, and of course, what excursion into weeds and wildflowers wouldn't be appropriate without mentioning the California poppy (Eschscholzia californica), which, of course, is a beautiful plant, but could be considered a weed to many.

 

 

 The wild calendula in my garden developed as a surprise. Several years ago, I bought a package of calendula seeds - most likely Calendula officinalis. They produce gorgeous, low-to-the-ground plants with attractive three-inch orange and yellow flowers. I did not buy them with the intention of using them as ground cover, but they became ground cover! Several years later, those plants still reappeared since they could be self-sown.

 

 

 

 

To my surprise, I noticed that one part of my garden had these much taller daisy-like plants that I discovered were a different type of calendula, often called field marigolds, Calendula arvensis. I'm not sure how Calendula arvensis came to my garden. I have purchased several packs of wildflower seeds over the years. Perhaps it was brought into my garden by one of those wildflower mixes.

Since we live in a Mediterranean-type climate, this should not come as a surprise. These plants are often found in fields in the Tuscan region, especially among olive groves. The blooms are much smaller than the calendula that I started from seed. I enjoy how they open every morning, follow the sun, and close in the evenings. Often, visitors to my garden confuse them with blooming mustard plants, commonly seen here in the Valley at this time of year as cover crops between the grape vines.

 

What is also spectacular about both of these calendulas is that they seem to be very drought-tolerant. I don't use much, if any, water for either and am constantly rewarded with a multitude of blooms. The more cultivated calendula continues to bloom well into the summer with infrequent watering. The wild calendula gets “leggy” after a while. I pull them up by late April, amend the soil, and plant my sunflower seeds.  It's a great spot in my garden to keep a continuous pop of color.

 Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143.  Volunteers will get back to you after they research answers to your questions.

Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.

Photo credits: Lonnie Clark

How a quick detour became a highlight of our trip to the Coachella Valley Indian Wells Tennis Tournament.

Indian Wells in March is a veritable paradise of 75-80° weather, blooming citrus trees, an effortless blend of thriving Mediterranean and desert plants and world class tennis. This year, however, there were some unusual winds, rain and even bee swarms that affected the tournament schedule. 

We decided to use this intermission to explore the area and drove out to the Thousand Palms Oasis Preserve located on the trace of the San Andreas Fault.  The preserve itself is a miracle of an ecosystem where majestic California Fan Palms are thriving in a swamp of sulfurous water in various otherworldly formations. It is also home to multiple native plants like Honey Mesquite, Goldenbush, Arroweed, Desert Holly, Cattle Spinach and many others.

Unfortunately, most of the trails were closed for rehabilitation due to the previous season rains, so we ended up driving around – which is how we came across some beautiful spots of blooming desert flowers.   Even though it was far from a super bloom (a bit early), it was still amazing to see this arid land spring back to life in vibrant colors with the snow covered San Jasinto Mountains in the background.

Most of what we saw were vast expanses of purple Desert Sand Verbena (25 species in western North America and 8 native to California!) and Silver Lupin with occasional blotches of yellow Brittlebush and white Burrobrush.

Up close, you can see how the desert plants maximize the use of water: their leaves are small and often covered in hair or wax. Some have succulent water-storing stems.  I was madly taking pictures hoping to identify them later using the most excellent Matt Ritter book, California Plants: A Guide to Our Iconic Flora. Shown below are a few I encountered:

 

 

 

Pincushion Flower (Chaenactis fremontii) -- native to Mojave and Sonora, it is one of the most conspicuous spring wild flowers and a valuable source of food for desert tortoises.

 

 

 

 

 

 

 

California Figwort (Scrophularia californica) – with slightly fragrant flowers attracting local bees, butterflies and birds.

 

 

 

 

 

 

 

Scorpion Weed (Heliotrope phacelia) – beautiful, but, as the name implies, dangerous – can cause rash. 

 

 

 

The wildflower season is just beginning and, given the amount of rains we have had lately, another super bloom season is in the making. You don't need to drive to Coachella Valley to enjoy it. Plenty of places locally in Napa County:  Moore Creek Park in St. Helena, Alston Park in Napa, Oat Hill Mine Trail in Calistoga and Bothe-Napa State Park.

Get out your Audubon Field Guide to Wildflowers and go!

Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143.  Volunteers will get back to you after they research answers to your questions.

Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.

Photo credits:  Natasha Mantle