By Melody Kendall

This is the second of four articles describing plants and their care featured in the UC Master Gardeners of Napa County's low water, low maintenance area at the Las Flores Learning Garden.

Raywood Ash,with the Latin name of Fraxinus oxycarpa (or angustifolia) 'Raywood,'  reaches to a maximum height of 50 feet and a canopy width of 20-30 feet.  With a lower trunk of a light gray rough bark and upper branches of smooth gray, this tree has the possibility of growing up to 24 inches in a year until its final height is reached. Raywood ash has spear-shaped, 3-4 inch leaves that turn a wonderful deep red in the fall and then drop in early winter.  As with other deciduous trees, leaves are somewhat of a mess to clean up, but no other debris during the rest of the year, other than occasional small branches broken during heavy winds, are in evidence. It requires little or no pruning to shape as it grows.  As safety first should always be observed,  pruning of a full size Raywood ash may best be left to a professional.  Considered to be smog tolerant and having roots that tend to be deep, these trees can be planted in a row at least 10 feet apart to create a screen. They are deer resistant and grow best in full sun or part shade. When stressed, these trees have some susceptibility to root rot, sooty mold, verticillium, beetle borers, scales and white fly, but are resistant to armillaria. Raywood ash is less drought tolerant than previously believed, so occasional deep watering during the drought season and pruning to thin canopies will help keep the tree healthy and avoid stress.

Crape Myrtle, Lagerstroemia indica seems to be ubiquitous in many landscape designs and a frequently seen street tree in our valley. The crape myrtle can be grown as a single trunk or multi-trunk tree or a bush. They reach a maximum height of 15 feet with a canopy width of 6-15 feet, depending on which form is desired. Multi-trunked trees can require some pruning and shaping. This maintenance can be accomplished without a professional as they are not that tall. The deciduous leaves are oval and bronze, purple or reddish. Myrtles come in a wide range of colors, including white, lilac, and purple, many shades of pink and different shades of red.  Again, being deciduous means fall cleanup of leaves, but there are other litter issues with the crape myrtles, too. In spring, flowers fall and in fall fruit drops along with striking light green, pink or red brown bark that exfoliates regularly, exposing smooth bark underneath. All of this contributes to continuous cleanup needs. Crape myrtles, when stressed, have a susceptibility to sooty mold and aphids. On the plus side, these trees require little water once established, are deer resistant, attract birds and bees and are resistant to powdery mildew.  These lovely little trees provide wonderful, continuous visual interest with their curving multiple trunks, lovely leaf and bark color and a bountiful colorful floral display each spring.

Strawberry Madrone, Arbutus unedo is native to southern Europe and Ireland. These rounded or vase shaped trees have evergreen oblong shiny dark green leaves and colorful red-brown exfoliating bark. Arbutus can be grown as multi-trunked shrubs or tree form. The pink and white lantern shaped flowers are sprinkled all over the canopy of the tree or shrub and attract hummingbirds. The inch long rounded fruit is sparkly bright yellow and red dangle throughout the foliage. The fruit is edible to humans but mealy and bland in texture and somewhat messy, but wildlife like to eat it. Interestingly, flowers and fruit seem to be produced on a rotating basis all year in our area. Once established, trees grow to 35 feet tall and wide and require only occasional deep summer watering. These trees don't need pruning except to keep their height to your preference.  Plant in full sun to part shade and in well-drained soil. Fertilizer isn't needed and the trees are reasonably pest free.  Some possible problems might be anthracnose, phytophthora, root rot, rust, scale and thrips, but arbutus does have a resistance to armillaria.  These trees make quite a statement in a row with their lovely shape, cool striated bark, pink/white flowers and red and yellow fruit.

In conclusion, once established, these three trees require little water and maintenance. Additionally, each can be counted on to demonstrate visual interest at some point during the year.

The UC Master Gardeners and the City of Napa have joined in a partnership at the Las Flores Community Center where instructional events are planned for the last Saturday of the month through 2022. Topics will center on research-based horticultural and climate change issues by featuring water saving plants and soil care.

Next week, in the third installment of these articles, we will talk about the Yellow-twig dogwood, Loropetalum and Meyeri fern.

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: Olga Morham

Information links: Raywood Ash: https://selectree.calpoly.edu/tree-detail/634

Crape Myrtle http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/crapemyrtle.html

Strawberry Madrone https://selectree.calpoly.edu/tree-detail/177

UC IPM Root rot http://ipm.ucanr.edu/PMG/PESTNOTES/pn74133.html#:~:text=Death%20in%20California.-,SYMPTOMS,Phytophthora%20rot%20appear%20drought%20stressed.&text=Phytophthora%20infections%20typically%20kill%20young,of%20a%20tree%20or%20plant.

Verticillium http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/vertwilt.html

Beetle Borers http://ipm.ucanr.edu/PMG/invertebrates/links.beetles-treeborers.html

White fly http://ipm.ucanr.edu/PMG/PESTNOTES/pn7401.html

Armillaria http://ipm.ucanr.edu/PMG/PESTNOTES/pn74171.html

Anthracnosehttp://ipm.ucanr.edu/PMG/PESTNOTES/pn7420.html

Thrips http://ipm.ucanr.edu/PMG/PESTNOTES/pn7429.html

 

 

 

 

 

 

 

by Melody Kendall

This is the first of four articles describing plants and their care featured in the UC Master Gardeners of Napa County's low water, low maintenance area of Las Flores Learning Garden.

Little ‘Ollie' Olive

This little gem is a miniature fruitless olive variety whose Latin name is Olea europaea.  Olives are native to the lands around the Mediterranean Sea and olive leaves are considered the enduring symbol of peace. The ‘Little Ollie' variety is evergreen and fruitless with small, insignificant flowers that still attract birds and bees in the spring.  Planted in loose well-draining soil, this small olive displays dense green leaves with silver undersides.  When the wind blows its leaves, shiny when new and fading into matte when mature, their silver undersides flutter and the plant appears to shimmer.

Perfectly happy in containers as patio specimen plants, trimmed and formed in hedges or just allowed to thrive “as is,” this plant needs full sun and enjoys the heat.  Once established, the ‘Little Ollie' Olive needs little water, requiring only regular water during extremely dry conditions.  Though virtually pest free these plants can get root rot if overwatered and sometimes suffer scale insect infestations.  If these plants are left “as is” they only need occasional pruning to keep the desired 4 foot by 6 foot wide and tall globular shape.  They can be trained into one or multiple trunks and as a hedge by shearing rather than hand pruning for shape. While not needing any regular amendments or fertilizers, compost added to the soil is always well received. 

Star Jasmine

This plant's Latin name is Trachelosperum jasminoides and it is a member of the Dogbane or Apocynaceae family.  The family name Dogbane comes from the Greek word apocynum meaning "dog-away" a reference to the fact that some taxa were used as dog poison. Also, the plants in this family, when cut, have a white milky sap that can be a skin irritant, gum up tools and stain clothing. Star jasmine is native to eastern and southeastern Asia.  With bright shiny leaves, sweet smelling white flowers in spring and a vining growth habit, these plants lend themselves well to arbors and can grow to 20-30 feet when supported.  They also do well as a ground covering plant growing to 3 feet tall with a 3-6 foot spread.  Do be aware of the star jasmine's tendency to climb and invade surrounding plants. Plant in well-draining soil 5 feet apart in full sun.  Once established, plants tolerate drought conditions with additional water during extreme heat. star jasmine is virtually pest free with only mealy bugs, sooty mold and scale a slight possibility.  Fertilizing isn't recommended as application tends to reduce production of its sweet-smelling flowers, though compost is well received at any time. Pruning this plant depends on how it is displayed. If it is flowing up a fence or trellis, keep the wild shoots trimmed back to keep the form and to help reduce the weight on the structure. As a ground cover, contain the total size of the plant to keep the vines from overwhelming neighboring plants. A hedge trimmer works well to maintain both the vertical and horizontal growing methods.

Pink Muhly Grass

Latin name Muhlenbergia capillaris, pink muhly grass is a member of the grass plant family and native to Florida and Eastern U.S.  This plant is evergreen in temperate areas and deciduous in colder climates. The pink muhly grass's long narrow upright leaves and stems lend vertical interest to the garden and in containers when mixed with other plants. In the late fall this grass plant grows stems 12 inches tall that sport fluffy, feathery pink blooms. When planted singly, in clumps in the garden or on hillsides to prevent erosion, this display of pink cotton candy like blooms is quite spectacular.  Pink muhly grass doesn't like wet feet so plant in well-draining soil in full sun. Once established, water sparingly but remember to water more regularly in very dry conditions.  This grass plant has few pests, is deer resistant and attracts ladybugs.  Seeming to thrive on neglect, the management of pink muhly grass is very easy.  As with the other two plants, fertilizer isn't needed. If the grass goes dormant in the late winter, they can be cut to within 6 inches from the ground. In different climate zones of Napa Valley some go dormant and others remain green all year. This grass can be divided into smaller clumps and replanted if they get too large in late winter. If they remain green the removal of spent blooms is all that is required, though the spent blooms provide late winter seeds for the birds.

In conclusion, once established, these three plants require little water and maintenance. In addition, the plants can be counted on to demonstrate visual interest sometime throughout the year.

The UC Master Gardeners and the City of Napa have joined in a partnership at the Las Flores Community Center where instructional events are planned for the last Saturday of the month through 2022. Topics will center on research-based horticultural and climate change issues by featuring water saving plants and soil care.

The first event of 2022 will be held January 29th. showcasing the low-water, low maintenance area of the garden. Next week we will talk about the trees in the garden. The Raywood Ash Fraxinus oxycarpa 'Raywood', Crape Myrtle Lagerstroemia indica and the Strawberry Madrone Arbutus unedo.

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: Olga Morham

Information links:

Shrub pruning UC ANR blog https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=42943

Little ollie olive https://sonomamg.ucanr.edu/Plant_of_the_Month/Olea_europea/

Star Jasmine https://ipm.ucanr.edu/PMG/GARDEN/PLANTS/starjasmine.html

Pink Muhly grass https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=45732

UC IPM Mealybugs http://ipm.ucanr.edu/PMG/PESTNOTES/pn74174.html

Scale http://ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html

Sooty mold http://ipm.ucanr.edu/PMG/PESTNOTES/pn74108.html

 

by Mel Kendall

The focus of our new landscape was to create a low-maintenance pollinator magnet. Our research pointed us to the philosophy that what we planted had to have these two characteristics: low or no maintenance during the winter and summer and the requirement for only a few dedicated workdays in the spring and fall. The pollinators have arrived in droves, featuring multiple kinds of bees, butterflies and hummingbirds.

The fall of 2021 was our first year of fall maintenance. I use the words ‘installed' instead of ‘completed' because, in the words of a wise UC Master Gardener friend, “a garden is never completed, it evolves.” I have mentioned my preference for deciduous trees because they have set times for debris dispersal. Evergreen trees seem to be a constant maintenance issue with their leaf, flower, fruit and bark debris dropping on a continual basis. As a result, our trees are deciduous, but the shrubs are either evergreen or deciduous, depending on where they are in the landscape. The plants are chosen for their constant color and coverage. They have been working all summer producing their various raisons d'être: regular flower production for pollinators and ongoing green leaves that cover and protect the soil while providing constant color. Each of these plants has some basic maintenance, but not too much, keeping with our low-maintenance theme. 

- Daylilies (Hemerocallis) Some are deciduous and some are evergreen. All produce flowers on a regular basis and require little or no upkeep.  Removal of spent blooms and stems (called deadheading) on a regular basis and an early spring removal of dead leaves from the previous year's growth is all that's required.

- Red-hot poker (Kniphofia uvaria) We have three varieties of these plants and are very satisfied with their performance in the landscape.  All three are evergreen and produce long stems with flowers on a rotating basis. These plants fulfill their low-maintenance requirement admirably, only requiring removal of spent stems, blooms and leaves as needed. 

- Lantana (Lantana camara) Evergreen and virtually maintenance free. To encourage reblooming, deadhead periodically. To contain overgrown plants just cut back a third of the plant's growth in the spring.

- Gaillardia- (Gaillardia spp.) Amazing flower power contained in each plant. Deadheading as needed will ensure their continued explosion of flowers. They are herbaceous, with leaves that die back in the fall and reemerge in the spring.  Each plant should be cut back to 6 inches from the ground in the fall. 

- Russian Sage (Perovskia atriplicifolia) Spring and summer care consists mainly of pruning. When new spring growth emerges in spring, cut the old stems back to just above the lowest set of leaves. If the plant begins to sprawl in the summer, cut off the top one-third of the stems to encourage more upright growth. If the plant stops blooming in summer, remove the top half of the branches to encourage new growth and a fresh flush of flowers.

- Roses (Rosa spp.) Roses usually don't go completely dormant in our climate zone but wait until late winter before pruning. Remove all the old leaves, prune out weak, spindly or diseased canes at the base, remove any canes crossing through the center, then prune remaining canes back by one-third to one-half.

- Bulbine (Bulbine frutescens) An evergreen globular plant that blooms nearly all year long.  Removing the spent flower stalks periodically to neaten their appearance is all that is needed.

Fall brings leaf drop in our deciduous trees and shrubs. After the leaves have fallen, we can see all the branches, making it easier to prune for shape and maintenance. The trumpet vines (Campsis radicans) growing on the fence only require thinning and cutting off any shoots that have outgrown their designated areas.  If allowed, these vines have the potential to “take over” and possibly overburden the fence, so thinning and maintaining is a must.

The trees, depending on their growth habit, required some thinning and shaping to allow them to fill out areas as desired.  Our maple, Acer ‘Warrenred' PACIFIC SUNSET^® is growing perfectly, both in height and canopy width.  For now, we are leaving it alone. The smoke tree (Cotinus x 'Grace') sent out long branches all over the canopy that were cut back to their origin points after some research on how to prune them. Keep in mind that continued hard pruning will affect flower production, but will control the tree's size.  Our black locust (Robinia pseudoacacia ‘Twisty Baby'™) grew exponentially this last year.  After the leaves dropped, we were able to see the branches simplifying our pruning plans. We wanted to bring the branches up from the ground and thin them so the tree stayed the same height, but with a thinner and more open canopy.  As mentioned, this tree grows aggressively, so it will probably need more than cursory “finger pruning” of new growth.  

The first year of our new landscape has gone well, and we'll see how the plants we pruned this fall recover in the spring.  Hopefully, we didn't go too overboard and kill anything.  Regardless, we learned a lot about each plant and had fun doing this chore. Gardening in any form is always delightful for me, so excuse me while I don my gardening attire and head out to enjoy another day in my own special secret garden.

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: Mel Kendall

References:

American Daylily Society https://daylilies.org/

Missouri Botanical Garden-Kniphofia uvaria

https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=i310

UC IPM-Lantana http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/lantana.html

Monrovia -Gaillardiahttps://www.monrovia.com/sunset-snappy-blanket-flower.html

-Bulbine https://www.monrovia.com/orange-stalked-bulbine.html

Acer ‘Warrenred' PACIFIC SUNSET^® https://www.jfschmidt.com/pdfs/pacificsunsetmaple.pdf

Grace Smoke Tree Cotinus x 'Grace' UC Master Gardeners Sonoma County http://sonomamg.ucanr.edu/Plant_of_the_Month/Cotinus/

Robinia pseudoacacia Twisty Baby™ Oregon State

https://landscapeplants.oregonstate.edu/plants/robinia-pseudoacacia-twisty-baby

 

by Melody Kendall

Be careful what you wish for... the full saying is from Aesop's Fables and fully stated is: “Be careful what you wish for, lest it come true!” I have often heard this saying and its cautionary tale is applicable in many areas in my life experience over the years. Most recently, it is relevant to my gardening experience. Do you feel when you visit a friend's garden and/or a botanical garden finding yourself covetous of an area or the entire garden?  Then, when you implement a similar arrangement of plants and/or a complete duplication of the garden in your landscape, you find it doesn't match your expectations or plans?

My tales began five years ago.  I saw a wonderful waterfall-like display of morning glory flowers (Ipomoea purpurea or Convolvulus purpureus) in a friend's garden.  This wonderful fall of brightly colored blooms filled an entire area of the landscape and completely covered a broken-down old fence. My friend waxed eloquently about this plant's ability to self-seed and said that she had not needed to do any maintenance to acquire this amazing display.  I had to have some.  Purchasing some morning glory seeds and distributing them liberally in the chosen area of my landscape I waited anxiously for my own waterfall of morning glories. The first year I was disappointed by the display as it was rather sparse.  Now, five years later, I am fighting back the plants with a machete. Not really, but the morning glory plants pop up all over my landscape. Adding to the excitement, these plants climb on everything with virtually unbreakable vines that trip me at every chance. A good thing to note is that I have found that the tough shelled seeds, once thought to be toxic to birds, are in fact a food for songbirds and the nectar from the late blooming flowers provide food for pollinators, particularly hummingbirds.  To avoid “waterfalls” of these crazy growers all over my landscape I'm reduced to pulling out the seedlings everywhere before they start climbing. The morning glory plant is listed on the UC IPM Weed Gallery list — need I say more?

You might think that with all the time spent fighting the morning glory wars I would not have had time to get myself in plant trouble again.  Not so.  I was looking for a ground cover to fill in around some pavers and liked the look of Potentilla neumanniana ‘Nana.'  The plant filled the areas between the pavers within a year but, unfortunately, didn't stop there.  Recently, I pulled out some specimens in my rose garden forty feet away.  Plus, each year it gets a rust fungus that kills large swaths of them and is really unsightly.  These plants are good for bees, but not me.  I had come to believe the “poten” part of potentilla means it is a very potent ability to grow.  Instead, the genus name from Latin potens meaning “powerful” is in reference to the reputed medicinal properties of the plant. I like my definition better.

My brother lives on Vancouver Island, lucky him, and I visit every year.  I absolutely love the flowers and foliage that grow abundantly in the pacific northwest wonderland.  Their weather is much cooler and wetter than ours, but I still wanted to try some of their plants in my garden.  One of my favorites is the Oriental Poppy (Papaver orientale) and I succumbed to the urge and purchased some seeds. The seeds are very small, and I needed glasses to divide and distribute them evenly. The first year I wasn't impressed with their germination, maybe 1 in 20 grew. Without flowers the plants look very much like weeds.  When my daughter visited, she asked if I was having back problems. When I looked at her with a perplexed expression, she said she figured I must have a good reason for leaving all those weeds in the garden. We are entering the second year and, my goodness, the seeds that languished last year have decided to get off the duff and go gangbusters.  I now have what looks like a flourishing weed crop.  I can only hope that these plants produce the wonderful flowers. The cautionary portion is that I over-seeded the tiny seeds and thickly growing plants are the result of my overzealous broadcasting. Keep that in mind if you decide to grow them.

One final example will end my tale.  We have fences surrounding our city lot and in the interest of privacy and background greenery we planted star jasmine (Trachelospermum jasminoides) vines all along the perimeter.  For some reason these Star Jasmine died out in a couple of years, the reason never diagnosed, so we decided on the potato vine (Solanum jasminoides) as a replacement.  As a privacy screen and color the choice was a good one. The maintenance requirements are a nightmare. We have to cut it back aggressively almost every month, and in the spring and summer sometimes weekly.  Perhaps I should have thought more about the plant description comment ‘fast growing' when choosing this vine. 

Overall, I don't think that I would have done anything different in my garden.  Each of the above plants provide more pleasure than pain, but it would have been nice to be more aware of their growth habits going in. So, be careful what you wish for… lest it comes true. Things may not always turn out the way I had planned or envisioned in my garden, but I consistently learn something in the process. My advice, in hindsight, is to research, research research. I need to go out to my garden to pull up some of those pesky morning glory seedlings now.

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: Mel Kendall

References:

UC IPM-Morning glories http://ipm.ucanr.edu/PMG/WEEDS/morningglories.html

Monroe Outdoors-Terry Johnson-Wildlife biologist http://www.mymcr.net/our_community/monroe-outdoors-morning-glories-can-be-pests-but-always-beautiful/article_4a119fcc-fdcb-11ea-97df-dbc1356b221f.html

Missouri Botanical Garden Potentilla https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=252641&isprofile=0&

Oriental Poppy https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderProfileResults.aspx?basic=Papaver%20orientale

UC IPM-rust http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/rusts.html

Monrovia Potato Vine https://www.monrovia.com/potato-vine.html