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2011 Master Gardener Calendar - Coming in October
The Cool-Season Vegetable Garden: Peas
Plant tests bring "Arboretum All-Stars" to Home Gardeners
An "All-Stars" Experience: Learning about Natives by Trial-and-Error

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An "All-Stars" Experience: Learning about Natives by Trial-and-Error

By Hanna Richardson

My experience with the Arboretum All-Stars began with a request from the Master Gardener office for a coastal-area site for testing plants that UC Davis had identified as being drought tolerant and relatively pest free. The Master Gardener (MG) training had given me a strong background in many topics – soil, irrigation, fruit trees, vegetables and pests among them, but nothing specifically about natives or other drought tolerant plants. What a great opportunity! I could contribute to the greater good and add to my personal knowledge base.

The winter of 2005-06 brought record rainfall so the motivation to drastically cut landscape water use did not play a significant role in my volunteering. Recent water shortages have increased my interest in native and Mediterranean plants and the desire to make information on how to grow them more readily available.

In the beginning, Arboretum All-Stars project coordinator Karrie Reid, explained that she was not looking for special care for the trial plants. The program’s goal was to learn if these plants would survive, and maybe thrive, in a real garden in the southern California coastal environment.

My responsibilities included measuring the plants to record their growth and observing them to note their appearance, bloom cycle and susceptibility to diseases and pests. The monthly measurements and observations and the annual summary report provided a lot of insight, but I have learned so much more from the experience.

The trial plants included some that were really interesting but not generally available. Ceanothus ‘Marie Simon’, a semi-deciduous variety with pale pink flowers and red stems, is beautiful. Saponaria’ Max Frei’ has been in bloom 12 months of the year in full sun in my yard.

Sharing information with the public is a priority for Master Gardeners. My experience with the “Arboretum All-Stars” program validates our planting guidelines – particularly for native plants. I’d like to share them with you.

  • Group Plants by Water Needs – Receiving four or five different plants twice a year led me to “plunk” them into any available space that met the species’ needs. Integrating natives into a thirsty garden environment poses challenges. During the first summer, while they are getting established, their needs are similar to other plants. After that, problems arise when they get too much water. Unless you are replacing large areas with drought tolerant plants, my experience points out the advantages of “starting small” so it is easy to group plants by their water needs. My involvement with the “All-Stars” has motivated me to replace the foundation plants in my front yard with natives that only need summer water every three weeks. Other possibilities might include the strip beside your driveway, or any area served by a single irrigation station.

  • Select the Right Plant for the Location – Sun or shade, coastal or inland, mature plant size, water requirements: All of these plant characteristics play a role in deciding which plants to choose for specific places. Trial-and-error has been a good teacher.

Thinking that all iris like sun, I planted the Iris ‘Canyon Snow’, a Pacific Coast hybrid, in a southeast exposure that gets hot sun all winter. They baked! A little research would have told me they like dry shade. Now, in a northern exposure, their blooms in April and May have been gorgeous. 
Iris ‘Canyon Snow’
(photo: H. Richardson)

Karrie Reid helped me select a spot for the coral bells (). They looked so good the first year that Karrie used my photo for her first published results. Then they struggled and looked generally crispy around the edges. Moved to the shade, they are now thriving.
Heuchera rosada
(photo: H. Richardson)

The serpentine columbines (Aquilegia exima) were lovely nestled under the pineapple guava tree, but its hair-like roots were too much competition. The first year they seemed very happy, but then they went into a decline. Two of the three succumbed, but the other is now looking better than it has in years and is beginning to bud. Seedlings are appearing in the original location. I’m waiting for them to get big enough to transplant.
Aquilegia exima
(photo: H. Richardson)

  • The pine muhly grass (Muhlenbergia dubia) were tiny so I planted them close together to make them easy to care for. I knew their mature size was 3 feet by 3 feet, but had no clue they would achieve that in six months! Measuring them for the study was impossible. I’ve separated them and may transplant them again. They can fully develop in their new location, but do not flow with their surroundings.

  • Follow Planting Guidelines – Karrie Reid usually delivers plants in October/November and March. Fall is the ideal time to plant natives. The winter rains and cool temperatures give plants a chance to develop roots. Early spring is also good. She brings small plants. Many are in 4-inch pots; the largest have been in 1-gallon cans. They have been easy to establish. Now I know to irrigate them well at planting time, add a thick layer of mulch and keep them weed free.

  • Get Them Established – Today I know to keep the roots of native plants moist, but not soggy, during the first several months and maybe through the first summer. In the beginning, I violated these rules and lost the blue grama grass (Bouteloua gracilis). The first winter was especially dry.  My lack of understanding led me to believe that natives tolerate drought so I gave them no supplemental water. The following year a Ceanothus ‘Valley Violet’ died from too much water (thanks to a leaking sprinkler). My instinct when it looked poorly was to give it more water – exactly the wrong approach. By the time I discovered the real problem, it was too late.

  • Heed Summer Water Requirements – California natives have varying summer water needs. Most want water once or twice a month. Some want no water at all. A few like it moist. It’s been culture shock to shift from my typical twice weekly irrigation schedule to once or twice a month. Weathering the learning curve has enabled me to proudly say that many parts of my yard are now irrigated only occasionally. I have converted the foundation plants in my front yard to natives and other drought tolerant varieties. They are being watered every three weeks and are thriving. In other locations the natives are serving as anchors as the low water use areas expand. This summer I plan to irrigate once or twice a month with supplemental hand watering of a few individual thirsty plants.

- Hanna Richardson is a Master Gardener and member of the SD Horticultural Society. As a former teacher and instructional designer, she especially enjoys helping other gardeners gain insight and solve problems. She designs and develops the exhibits that support Master Gardeners at events. Most recently, her gardening has focused on converting a thirsty, high-maintenance landscape to one that requires less work and less water. She takes great pleasure all aspects of gardening - especially in growing fruits and vegetables.