By Brent McGhie, Butte County Master Gardener, December 23, 2016.
There are several advantages to planting bare-root trees: they are usually less expensive, easier for gardeners to transport, and they will grow their roots entirely into native soil (rather than having to transition from potting mix into dissimilar native soil). Also, the ideal time to plant bare-root trees is in the winter, when you have a break from the demands of other garden chores.
Once the planting site has been prepared, it's time to select the tree. Trees with a trunk diameter between one-half and five-eighths of an inch usually become established faster than larger or smaller stock. If the root mass is visible, be sure it is well balanced, not “one-sided.” Remove any dead or damaged roots before planting. It is best to plant bare-root trees immediately after bringing them home, but if this is not possible, the roots should be covered with sawdust or compost and kept moist until planting.
To prevent the tree from settling too low in the ground, dig the planting hole no deeper than the tree's roots. To encourage root growth, the hole should be about twice as wide as the spread of the roots. If the soil contains a large amount of clay, the sides of the hole should be scored to aid outward root growth. Build a cone of soil in the center of the hole and spread the roots over the cone, with the bud union (where the tree was grafted onto the root stock) facing south west. This prevents sun-scald of the flat side of the trunk just above the bud union. Next, back-fill the hole with the same soil that was taken from it until the hole is half filled and gently firm the soil to eliminate large air pockets. Double check the planting depth, making sure the bud union is four to six inches above the soil surface. Finish filling the hole with the native soil and gently firm it once again. When properly planted, the tree's uppermost roots should be just slightly below the soil surface and the soil should slope gently away from the trunk, preventing water from accumulating there.
Thoroughly water the newly-planted tree to settle the soil around the roots. Unless the tree has been planted in wet, heavy clay soil, a basin should be built around the tree. (In clay soils, keeping the soil too wet can eliminate air spaces in the soil, “suffocating” the roots). The basin should be donut-shaped, with the tree sitting in an island of soil in the middle of the basin. Again, to discourage rot, make sure water drains away from the tree. The basin should be slightly wider than the planting hole, ensuring that the entire root area receives water. After growth has begun in spring, water the new tree once or twice per week, adjusting the schedule as needed for cool rainy periods or early hot spells.
Clear an area about 3 feet wide around the tree, eliminating weeds and grasses to keep them from competing with the tree for water and nutrients. To prevent future weed growth and conserve moisture, a layer of mulch 3 to 6 inches thick can be placed around the tree. However, to avoid crown rot, keep the mulch several inches away from the tree trunk. As a final step, remove the top of the tree by pruning back to a single trunk approximately 24 inches tall and paint the bark of the entire tree trunk with white interior latex paint diluted with water (two parts water to one part paint) as a whitewash to reflect excess heat. This prevents sunburn and the resulting invasion of wood-boring insects that can stunt or kill the new tree.
By Carolyn Melf, Butte County Master Gardener, November 11, 2016.
At this time of year bulbs are appearing at nurseries and big retail stores as well as in the garden catalogs that arrive in your mail box. Many bulbs (like tulips) need to be chilled for 8-10 weeks in your refrigerator before replanting for blooms the following spring. Consider growing bulbs that are better suited to our warm climate. They are easier to grow, most are perennial, and they look their best in warm temperatures.
Since most failure with bulbs can be traced back to problems during planting, give yourself time for proper planning and planting. Plant in November to early December in our mild climate urban areas (zones 8 and 9). Bulbs must be planted at the correct depth, usually in a hole 3 times as deep as the size of the bulb. Fertilizing with a bulb booster (such as 4-12-8) or with organic bulb food is a good idea: place a few grains of the fertilizer in the bottom of the hole, cover with a fine layer of soil so the bulb does not come into direct contact with the material, and then add the bulb and fill the hole with soil. “Which end of the bulb is up?” you might wonder --- usually the pointy end is up, and the roots face downwards. But some bulbs are long and narrow, making it difficult to tell which end is the top. You can plant such a bulb on its side – growth will respond to gravity with shoots growing up and roots growing down. After covering the bulbs with soil, water the planted area well. Moisture must be present 6 to 8 inches below the surface to encourage root growth. Finally, avoid walking on the bulbs and compacting the soil.
Alliums are ornamental cousins of onions that aren't usually bothered by animals. Globular clusters of white, yellow, pink, red, blue or purple flowers are carried on stalks that rise above the foliage. They come in a variety heights, as well as colors, and can blend into any garden.
Crinum, a tall member of the amaryllis family, is topped with a circle of trumpet-shaped flowers, usually white, pink or a combination of both. Plant so the neck of the bulb is just above the soil and give it plenty of water while it is growing.
Gloriosa Lily is a tuberous perennial with red and yellow lily-like flower heads. It can sprawl and scramble through other plants, climbing by means of tendrils at the ends of its leaves. Plant 1 to 2 inches deep, and 10 to 15 inches apart, in rich soil.
Watsonia has tallspikes of tubular blossoms which come in shades of red, orange, pink and white. They begin blooming in late winter and carry on into the spring.
By Laura Lukes, Butte County Master Gardener, October 7, 2016.
Gardening Within Our Means explores climate trends, and what they mean for our future. It's a well-researched, careful analysis of our Mediterranean climate, historic climate patterns, and water supply.
Alosi says that “climate change and the ongoing California dry period has produced a wealth of graphical information. I became intrigued with this information and how it related to gardening in California.” Her interest was whetted further when she heard the term “fake rain” used to refer to irrigation.
California: A Floristic Hotspot in a Mediterranean Climate
“We live in a ‘Hotspot' - the California Floristic Provence. It's one of five Mediterranean climates, all characterized by long, hot, dry summers” says Alosi. Given the variable nature of California rainfall, “our tradition of landscaping has not been climate appropriate.”
A “Hotspot” is rich in biodiversity and also threatened with destruction. Hotspots support half of all plant and animal species on Earth. The California Floristic Province stretches from southwest Oregon to northern Baja, and from the coast to the Sierra Nevada.
Atmospheric Rivers
Water Supply, Temperatures, and Groundwater
One-third of our annual supply of water comes from the Sierra Nevada snowpack. Alosi's research shows that “we are facing a decrease in future snowpack due to climate change and higher temperatures.”
Satellite photos show enormous decreases in the Sierra Nevada snowpack from 2011 to 2014. The winter of 2015 most likely gave us the lowest snowpack in 500 years. That year also was the hottest year ever recorded. The combination of low precipitation and high temperatures is especially damaging to our groundwater supplies. “And 2016 is on pace to be the hottest year yet,” adds Alosi.
In California, groundwater normally provides 40% of our water needs. In dry years, groundwater accounts for 50% to 75% of our water use.
Recent statistics show that some aquifers in California have been depleted by up to 50%. In some areas we've consumed twice as much groundwater as has been replenished through rain and snow.
Subsidence
Depleting groundwater storage has one important potential net result: Subsidence. The land surface sinks, reducing an aquifer's ability to store water.
The ground deep beneath our feet is filled with sediment, layers of clay, sand, and gravel from ancient lakes and streams. These layers hold water. In some areas, a layer of clay separates the shallow groundwater storage pockets from deeper aquifers. Over-pumping deeper formations can compress clay layers,due to the weight of the overlaying land, and they can permanently lose some of their ability to hold water. This has been particularly problematic on the west side of the San Joaquin Valley.
In economic terms, the damage to our infrastructure can amount to hundreds of millions of dollars: subsidence can damage canals that transfer water to the south; buckle roads and bridges; cause pipeline damage; and create fissures and depressions in the land itself.
How Did We Get Here?
Beginning in the 1850's, people from the Eastern US began to settle in California in large numbers, arriving with their favorite seeds and plants, and later importing exotic plants. The landscape style brought to California by emigrants originated primarily in northern Europe – where it not only rains a lot, but rains throughout the year.
Developments in drilling, pumping, and electrification resulted in irrigation with cheap, plentiful water, and unsustainable Eastern-style landscapes became the norm. In a few decades, the dry California landscape was transformed into lawns and thirsty ornamental plants.
Where Do We Go from Here?
When asked what she would like people to learn from her research, Alosi responded as follows:
“Current irrigation practices and our landscape design are not sustainable. And what scares me is that based on historical rainfall data, we are in a wet period! We've only gotten by because of our groundwater supply. Once that's gone, we're out of luck. The resources to maintain the current state of landscaping are dwindling quickly.
“Historically, no one really knew the state of our groundwater supply. With the scientific tools we have now, we have a better grasp of our conditions. Satellite images and tree ring analyses give us a much better sense of climate trends, and how they all interact. The latest technology allows us to understand what's going on with groundwater."
“What I find encouraging is that we are witnessing a move to a more sustainable model – lawn conversions, native plants, and the like. Social change moves slowly. But it's starting. And, by understanding our climate, we can, hopefully, learn to garden within our means.”
See Understanding Our Climate: Gardening Within Our Means:
- October 12, at OLLI's General Meeting at the Masonic Center. For more information, visit http://rce.csuchico.edu/event/2016-10/olli-2016-fall-general-meeting
- November 2, at the Master Gardeners Fall Workshop Series at the Demonstration Garden at Patrick Ranch. Registration is required at http://ucanr.edu/sites/bcmg/events/Workshops/
- November 21, at the Chico Horticultural Society Meeting. For more information, visit http://www.chicogardenclub.com/
- To schedule a showing of this presentation for your group, please contact the Butte County Master Gardener Office at 538-7201.
By Tom Hansen, Butte County Master Gardener, August 26, 2016.
Raspberries and some blackberries too are ready for the old canes to be removed and the new canes tied up. Grapes can have some of the excess leaves trimmed off to allow better air flow and ease your search during harvest. There is a lot to be done this time of year in the home orchard, so go out there and enjoy yourself.
By Carolyn Melf, Butte County Master Gardener, August 12, 2016.
If you haven't trimmed and divided your iris this summer, now is the time to do it.
Bearded iris plants need to be thinned or divided every 3-5 years. A single rhizome sprouts new rhizome offshoots many times over the years, developing into a heavy crisscross clump, often choked with old leafless rhizomes. Eventually the mass of leaves will exclude sun and air from the roots. This will lead to poor flowering and often weakens the plants, making them more susceptible to insects and diseases.
With a sharp stream of water from a garden hose, remove all soil from the roots and rhizomes. Trim roots to about 3 inches and trim the leaf fans to 6 inches to prevent them from tipping over when you replant them. Let them dry before replanting.
Iris are greedy plants and prefer to be placed in virgin soil, but you can fool them by amending the soil with well-composted planting mix. Rhizomes should be placed 18 to 24 inches apart. For each one, dig a hole, place a mound of soil in the center of the hole, then place the rhizome on the mound and spread its roots downward. Cover with 1 inch of soil. Don't plant them too deep! Plant additional leaf fans in the planting bed facing the same direction. This way the rhizomes will all grow in the same direction and there will be less crowding.
Newly-set plants need moisture to help their root systems become established. Water weekly if the weather is dry.
Iris will bloom sparsely the first year after planting but will bloom well in the second and third years.