Know Your Fruit Tree Rootstocks

Whether you are bare root fruit tree shopping in winter or picking out containerized fruit trees in other times of the year, read the label on the tree. Both of them.

After you're done salivating over the fruit's juicy details after reading the top tag, pay attention to that bottom label.

That tag, the rootstock information, is critical in determining whether the tree will live or die in your soil.

Fruit trees are grafted onto various rootstocks to extend the range for that tree, giving it the ability to grow where it might not normally be possible (due to sandy soils, wet soils, crown rots, nematodes, etc.). Rootstocks can also help control the height of the tree or offer drought tolerance or more protection in cold winter areas.

But no single root stock is perfect. Each has its pros and cons.

Here is a list of some of the more commonly available rootstocks for deciduous fruit trees, along with their pros and cons, according to wholesale fruit tree grower, Dave Wilson Nursery:

Nemaguard  peach seedling

    

Pros root-knot nematode resistant, vigorous, strong tree.

Cons susceptible to root-lesion nematode, prefers sandy soil, susceptible to oak root fungus; bacterial canker, prunes on this rootstock are subject to brown line

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Lovell peach seedling

     

Pros slightly more resistant to wet conditions than Nemaguard but prefers well-drained soils, slightly more resistant to bacterial canker than Nemaguard.

  

Cons susceptible to root-knot and root-lesion nematode and to oak-root fungus, some what susceptible to bacterial canker, prunes on this rootstock are subject to brown line.

 

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Citation  interspecific peach plum-rooted cutting

Pros highly compatible with apricot and plum, induces early bearing, tolerant of wet soil conditions, resists root knot nematode, advances maturity and increases size and sugar content of fruit.

Cons susceptible to crown gall, bacterial canker and oak root fungus, intolerant of virus with peach or nectarine.

 

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Viking interspecific peach, almond, plum; apricot-rooted cutting (patented)

    

Pros vigorous, root-knot nematode resistance similar to Nemaguard, productive, precocious tree, increases fruit size, considered well anchored, less susceptible to bacterial canker than seedling rootstocks, tolerant of wet soil conditions, tolerant of saline and alkaline soil conditions.

Cons Trees on peach x almond hybrid rootstocks, including interspecifics, are very sensitive to dehydration. While planting, keep roots damp. Irrigate after planting.

 

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Atlas interspecific (patented) peach, almond, plum; apricot-rooted cutting

Pros extremely vigorous, root-knot nematode resistance similar to Nemaguard, productive, increases fruit size, considered well anchored, tolerant of saline and alkaline soil conditions.

    

Cons delays fruit maturity in some varieties, intolerant of wet soil conditions, intolerant of dehydration in transplanting.

 

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Titan Hybrid Titan almond x Nemaguard peach hybrid seedling

    

Pros extremely vigorous, may have root-knot nematode resistance, considered well anchored, tolerant of calcareous soil conditions.

Cons trees may be excessively vigorous on good soil, may delay maturity of fruit, more susceptible to crown rot than peach seedling rootstocks, intolerant of wet soil conditions.

 

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Myrobalan 29-C plum-rooted cutting

Pros makes large tree, immune to root-knot nematode, tolerates wet soils, less sucker development than Marianna 2624.

Cons tends to lean, some incompatibility with almonds, prunes subject to brown line on this rootstock, may set lighter crop than Marianna 2624, susceptible to oak root fungus.

 

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Marianna 2624 plum-rooted cutting

     

Pros slightly dwarfing, moderately resistant to Phytophthora crown and root rot and oak root fungus, tolerates wet soils, root-knot nematode resistant.

Cons tends to lean; shallow roots the first few years, very susceptible to bacterial canker, incompatible with peaches, nectarines and some almond varieties, suckers profusely, susceptible to crown gall, almonds subject to brown line disease and union mild etch.

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Mazzard  cherry seedling

Pros more water tolerant than Mahaleb, cold hardy, resists root-knot nematode, vigorous, moderately resistant to oak root fungus.

Cons slow to bear, large tree prone to root suckering, susceptible to crown gall, bacterial canker; root-lesion nematode, scion doesn't show buckskin infection as quickly as on Mahaleb.

 

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Mahaleb cherry seedling

Pros more drought tolerant than Mazzard, resists bacterial canker, smaller tree than Mazzard, moderately resistant to crown gall and root-lesion nematode, shows buckskin infection quickly.

Cons intolerant of wet heavy soils, attracts gophers, tends to sucker, susceptible to oak root fungus, some root-knot nematode susceptibility - very susceptible to Phytophthora crown and root rot and Prunus stem pitting.

 

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Colt (patented) cherry rooted cutting

Pros tolerates wet heavy soils better than Mahaleb, resists bacterial canker; cherries on Colt are field resistant to cherry stem pitting.

Cons drought sensitive, slight to not dwarfing under California irrigated conditions, susceptible to crown gall, not cold hardy (not a problem in California).

 

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M 9 apple layered cutting

Pros dwarfs to 40-45% seedling size, very precocious and productive, increases fruit size, has field resistance to cherry stem pitting disease.

Cons shallow rooted, drought sensitive, trees require support, susceptible to fireblight and wooly apple aphid.

 

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M 26 apple layered cutting

Pros dwarfs to 55-60% seedling size, precocious and productive.

Cons shallow rooted; drought sensitive, staking or trellis usually required, susceptible to Phytophthora, susceptible to fireblight and wooly apple aphid.

 

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M 7 apple layered cutting

Pros dwarfs to 65-70% seedling size, widely adapted to various soil conditions, moderately resistant to Phytophthora.

Cons suckers, staking may be required, susceptible to wooly apple aphid.

 

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M 111  apple layered cutting 

Pros tolerates waterlogging and drought, well-anchored, resists wooly apple aphid, dwarfs to 90% of seedling-rooted size, good for sandy soils.

Cons susceptible to crown rot under very poor conditions.

 

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NCB (Northern California Black) walnut seedling 

    

Pros vigorous, resists Verticillium wilt, oak root fungus and root-knot nematode.

Cons susceptible to Phytophthora crown gall and root-lesion nematode, Persian (English) walnut on Northern California Black subject to black line.

 

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Paradox NCB x Persian walnut hybrid seedling

Pros very vigorous, may induce better quality and productivity. Resists root-lesion nematode and certain Phytophthora species, grows better in heavy, wet or low fertility soils than NCB, resistant to oak root fungus.     

Cons highly susceptible to crown gall, may be less resistant to oak root fungus than Northern California Black, Persian walnuts on Paradox subject to black line.

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Generally, your local, independently-owned nursery will pick the combinations of fruit tree and rootstock that will work best in your area.

Growing Citrus in Containers

Welcome to "Lazy Video Friday" here at the Farmer Fred Rant! 

California Heartland Video - Homegrown: Citrus in Containers

Despite What Your Smart Phone Says, All Gardening is Local

     Don Shor of Redwood Barn Nursery in Davis passes along this conversation between a customer and a nursery employee. A conversation - or one similar - which is probably repeated in nurseries every day:

“It says here that fava beans are planted in the spring,” says the young man.
“Says where?” asks the trained nursery person.
“Here,” as he points to his phone.
He has Googled a web site about vegetable gardening.
Ah, the new technology.


All gardening is local. But to get local garden information online, one needs to limit their Google search. One tip we have passed along before: when researching a plant or a pest, include the initials of the closest agricultural-based university. Here in California, that would be "UC".

To use the fava bean example: an online search that only included the phrase, "growing fava beans" returns a blog page as the first result, which states: "Fava beans are cool weather crops, and should be planted as early in the spring as possible." A little detective work on the origin of that blog turns up the authors' location: the Netherlands. Not exactly local. Not exactly a climate that resembles Davis, California.

Now, Google the phrase, "growing fava beans UC". At the top of that list? Information from the UC Cooperative Extension's Gary Hickman, longtime Farm Advisor in the San Joaquin Valley (local!). So, when does a gardener plant fava beans here? It depends on your intentions. "The fava bean is a cool-season annual legume and is usually planted February and March in California for vegetable use and September to November for cover crops."


Now, an argument can be made that perhaps the customer at the nursery intended to plant fava beans for harvest. Usually, though, anyone inquiring about fava beans this time of year is thinking "cover crop". And fava beans are a very good cover crop.

Callers to the radio shows or questions to the Farmer Fred e-mail bag are no different. Someone is always trying to grow something that is not intended for our area.

     Roberta of Carmichael (Sacramento County) is trying to emulate Johnny Appleseed:

      "I have two Maiden Blush apple trees in my yard. They ripen in August (which isn't very good). Is there anything I can do to make them ripen later in the year? I grew these trees from seeds from apples off a tree that was on my family's homestead in Nebraska. They are about 15 years old. This year, they seem to have gotten worm holes and not matured as well. Are they prone to any pests or diseases? What about watering? They seemed to have done OK so far, but i want to keep them healthy and alive!"

Depending on your location, the Maiden Blush apple can ripen as early as mid-August or as late as mid- September. The Maiden Blush was introduced into commerce in New Jersey, in the early 1800's. It's a popular dessert apple in the Appalachian mountain regions.


According to fruit tree nursery consultant Ed Laivo, that tree may be producing fruit early because it is stressed due to our summer weather: hot and dry, which is quite different from the tree's original production grounds in New Jersey (humid and rainy in the summer, with a pronounced winter chill). 

"We nicknamed Maiden Blush 'Maiden Mush' ", says  Kevin Hauser , the owner of Kuffel Creek Apple Nursery  in Riverside, CA.

And a stressed tree is an invitation to pests and diseases. Sort of like the slowest antelope in a pack, being chased by a lion. Or an aging catcher trying to steal second base.


The right plant in the right place. Sacramento may not be the right place for that Maiden Blush apple tree: 100 degree days, 15% humidity, and winter chill hours that are far below what is required for many eastern apple varieties. Winter chill hours are the total number of hours at 45 degrees or less between November and February. The Central Valley of California normally gets between 800 and 1200 chilling hours per year. Coastal California gets far less, ranging from near 0 (41 at La Jolla last winter) to about 400. There are plenty of apples that do well here in the Central Valley: Fuji, Granny Smith, Spitzenburg, Pink Lady, Gala, Ashmead's Kernel and many more. Their common trait: a winter chill requirement of 800 hours or less. Of those listed, several are taste test winners with winter chill needs that are far less than 800: Pink Lady (300-400 hours), Gala (400-500) and our personal favorite, Granny Smith (400 hours).


This is usually a line of questions I get from Bay Area or Southern California transplants to the Sacramento area or the foothills. They wonder why their bougainvillea dies in the winter here or why they can't get their Hass avocado tree to produce in the valley.  All gardening is local, especially in California, which according to the Sunset Western Garden Book, has 24 gardening climates. 

Having said that, let me repeat: All Gardening is Local. Actually, All Gardening is Really Local: you just might have the right microclimate in your backyard to grow plants that other gardeners struggle with in your neighborhood: Bananas in Lodi. Jacaranda trees in east Sacramento. And yes, bougainvillea that live year round...if you have the right conditions, and a lot of luck. 


A good reference book with lots of tips and tricks for growing plants in the Golden State: California Home Landscaping, by Lance Walheim.