UC Master Gardener Program
UC Master Gardener Program
UC Master Gardener Program
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UC Master Gardener Program

Latest Statewide Master Gardener News

Don’t Spring into Planting – Wait for the Threat of Frost to Subside

Frost damage to young tomato seedlings. Photo credit: Goldlocki
Seed catalogs have been coming in the mail for weeks showing off their new varieties and tempting home gardeners with harvest photos featuring vibrant fruits and veggies.  Don't let early spring like weather trick you into planting warm weather crops . . . just yet. 

Extreme heat or cold can cause damage to both cool and warm season vegetable crops.  Cool season vegetable crops like carrots, lettuce and broccoli bolt (premature flowering and seeding) when warm weather arrives.  Warm season vegetable crops like tomatoes, corn, beans and summer squash can easily be damaged by cooler weather and freezing temperatures.

As the transition from cool season vegetable crops to warm season vegetable crops occurs pay special attention to the weather and most importantly the frost date. Don't forget to harvest cool season crops before they bolt, and only plant warm season crops after the threat of frost.  

A cold frame provides a warm and protected space for your spring seeds, allowing gardeners to start gardening before the threat of frost as subsided. Photo credit: Sandy Metzger
To determine when the threat of frost is over use a frost date calendar, and read seed packets and plant labels for recommended planting times.  A frost date calendar is based on historical weather data and gives approximate dates of the first and last frost. Frost date calendars assist in determining when to plant and how long the growing season is in a particular area.

Time of planting, temperature and moisture all contribute to the success of a home vegetable garden.  If planted early, seeds may not successfully germinate and tender seedlings may be damaged by cold.  If planted late, vegetables may not have enough days to reach harvest.    

If you are eager to get your spring garden moving forward and can't wait until after the threat of frost has passed, here are some ways to extend your gardening season:  

Growing your own vegetables is rewarding when done properly, don't let poor planting practices ruin your harvest! Planning and preparation will help ensure the success of your crop, for more information on vegetable gardening and water-saving tips visit the University of California Garden Web

Resources: 

Last day http://www.plantmaps.com/interactive-california-last-frost-date-map.php
First day http://www.plantmaps.com/interactive-california-first-frost-date-map.php
http://cagardenweb.ucanr.edu/Your_Climate_Zone/

Sources: 
California Master Gardener Handbook, Chapter13 Home Gardening

 

Posted on Monday, March 14, 2016 at 1:29 PM

Little Less Conversation, Little More Action (Please)

I saw Elvis today. 

Actually, he's quite the regular at Sustainable Conservation's San Francisco headquarters these days. More than a titan among musical icons “The King” has become a muse to the PlantRight team, especially this National Invasive Species Awareness Week . We love Elvis' “A Little Less Conversation” because it might as well be our theme song for actionable awareness. We can't guarantee you'll be dancing along by the end of this article, but we do guarantee providing you with a few awareness-raising resources, a deeper understanding of what's holding back the hold-outs from taking positive action, and most importantly what we can do about it.

PlantRight defines “actionable awareness” as what happens when individuals and businesses are made aware of an opportunity to be part of the solution to California's costly (economically and environmentally) invasive garden plant problem, and make a conscious decision to act.  Invasive plants (despite the fact that many are deceptively beautiful and drought resistant) outcompete native plants, alter soil chemistry, increase wildfire risk, clog our waterways and can severely compromise agricultural yields and real estate value. If that weren't enough, invasive species are the second greatest threat to biodiversity after human development.

Awareness of these facts alone will not fix any of these issues; however, add action to the mix and you have a proven formula for problem solving.  PlantRight's idea of problem solving is collaborating with the industry to voluntarily phase invasive plants out of the supply chain and replace them with high-quality (i.e. non-invasive) plants. Voila! Together we prevent new invasive garden plants from wreaking havoc on our wild lands and taxpayer wallets.

Invasive species are second greatest threat to biodiversity after guess who …?
A Little Less Conversation, a Little More Action Please

The fact that 50% of California's invasive plants are of horticultural origin (Bell et al. 2007) is a source of both conversation and dismay.  Yet from PlantRight's perspective this 50% is a great source of optimism because it's proof of a huge opportunity the nursery industry can play in preventing future invasive plant introductions. In past decades ornamental plant breeders and growers had little or no ability to predict a plant's invasive risk in a given region, and most invasions were well-intentioned accidents.  Lucky for us we finally have science-based plant risk evaluation tools to prevent new invasive plant introductions.   Not so lucky for us is that popular plants travel, and a delightful Dr. Jekyll plant in one region, may become a hideous Mr. Hyde plant and landscape transformer in a different region. It's about the right plant in the right place, but just where to begin, if we're to turn this talk into actionable awareness?

In the beginning there was lots of conversation and lots of listening sessions that Sustainable Conservation conducted with a diverse group of nursery industry stakeholders, from large ornamental growers, retail nurseries, plant scientists, trade associations and government agencies. University of California Agriculture and Natural Resources (UC ANR) has been part of this group from the start, providing academic expertise on weeds and calculating their risk. This group's official moniker is “California Horticultural Invasive Prevention,” but we prefer Cal-HIP.

With a couple years of listening and learning under our belts, and funding from Sustainable Conservation, the PlantRight program was ready for action: action   engaging the nursery industry in voluntarily phasing our invasive ornamental plants and promoting, in their place, non-invasive alternatives.

Our first order of business was to measure the scope of the problem and establish a baseline. Working closely with plant science experts to identify the most problematic invasive ornamental plants, and industry experts to identify non-invasive alternatives, we created our first PlantRight plant list. If you can measure it you can manage it, we like to say - to do this, we rely on an annual Spring Nursery Survey. Each spring, partner with UC Master Gardener volunteers to survey more than 200 nurseries and garden centers around the state, and in the process track the retail market for invasive garden plants in California.

Along with informing PlantRight's program strategy, the annual survey allows us to keep PlantRight's plant list manageable and up to date – we add new invaders and retire those that are largely phased out of the trade.  It is our program's calling card, and the starting point for conversations with prospective partners and skeptics, alike.  It has earned the enthusiastic support of California Certified Nursery Professionals (CCNPro), SaveOurWater, and more.

A Little Less Fight, a Little More Spark

Buying non-invasive means many things, including protecting native species, being good stewards of our beautiful open spaces and waterways, being fiscally responsible and preventing additional taxpayer dollars going to avoidable invasive plant eradication efforts.  Buying non-invasive plants is casting a vote for the kind of world you want to live in.

So, why on earth do people buy invasive plants in the first place? (Hint: One big reason has to do with what happens when you turn off the lights). Yep, people who purchased invasive plants were in the dark – they did not know. 

In 2013, we learned that the primary drivers behind consumer purchases of invasive plants are: 1) aesthetics – it looks good; and, 2) there was no information on the plant indicating “invasive.”  In other words the majority of invasive plant purchases (by consumers) are impulse purchases and would not have occurred had the plant been properly identified as “invasive.”

Photo credit: Susan Morrison
Nan Sterman, award winning garden writer and host of PBS' “A Growing Passion,” has her own answer to this vexing invasive plant question.  “It's about visual influence,” says Sterman.  “People tend to buy and plant what they see in their local gardens and landscapes. “ According to Sterman, these include the very people who religiously recycle, buy high-efficiency appliances, and drive electric cars, yet they can't imagine beautiful, drought tolerant plants posing environmental problems.  Nassella tenuissima, or Mexican feathergrass, is one such culprit that has been romancing many well-intentioned Californians.

Come On, Come On…Come On, Come On

Ready to channel your inner Elvis and tackle invasive garden plant problems in ways that make economic sense?  (Of course you are!)  Here are a few resources to empower more action in your community.

So this National Invasive Species Awareness Week we encourage you to crank up that volume and bust a move with the PlantRight community (blue suede shoes optional), knowing that YOU are driving actionable awareness…this week, this month and in the years ahead.

Thank you, thankyouverymuch.

Posted on Wednesday, February 24, 2016 at 1:40 PM
  • Author: Jan Merryweather, PlantRight

Winter Care for your Peach and Nectarine Tree


Fruit mummies can harbor spores, fungus, and diseases which can ruin crops. (Photo credit: Jack Kelly Clark)
A successful summer harvest of peaches and nectarines starts in winter. General clean up, pruning, and dormant spraying will help prevent disease and keep your trees in good health.

Remove and destroy all mummified fruit hanging on tree branches or littering the ground. Although they look harmless mummies can harbor spores, fungus, and diseases which can ruin crops. Stop the cycle of infection by removing these mummies and destroying them, not composting them.


Distorted leaves with red blister-like swellings from leaf curl fungus on a peach tree. (Photo credit: Jack Kelly Clark)
Once the tree is dormant (no leaves) you can prune out any dead, diseased or broken branches. Do not seal or paint pruning cuts, leave them open to the air to heal naturally. Sealing or painting these cuts traps moisture and leads to disease. Once all dead, diseased and broken branches are removed prune up to 50 percent of last year's wood. Pruning your tree produces new growth and opens up the tree to sunlight to produce quality fruit.

Peach branch with approximately 10% of buds at full bloom stage. (Photo credit: Jack Kelly Clark)
To prevent leaf curl (fungus) spray before bud swell, which typically occurs after Feb. 14 or Valentine's Day. Signs of leaf curl are detected on new spring leaves but by then it is too late to control the disease. By planning ahead, you can reduce the likelihood of leaf curl and mitigate its effects on tree growth and fruit production. Some effective fungicide spray materials that are registered for backyard use are bordeaux mixture, fixed copper and chlorothalonil. Always wear proper protective clothing and follow the label when applying any pesticides.

For more information on winter, spring and summer care of your peach and nectarine trees see the University of California Agriculture and Natural Resources (UC ANR) Publication 7261: Peaches and Nectarines: Calendar of Operation for Home Gardeners.

For further assistance contact your local UC Master Gardener Program.

Sources:

http://homeorchard.ucanr.edu/Fruits_&_Nuts/Peach/
http://anrcatalog.ucanr.edu/pdf/8057.pdf
http://www.ipm.ucdavis.edu/PDF/PESTNOTES/pnleafcurl.pdf (Pest note7426)
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7481.html

Posted on Monday, February 1, 2016 at 1:16 PM
  • Author: Lauren Snowden

Get Informed! Online continuing education available about the Asian Citrus Psyllid (ACP)

Leaves with huanglongbing symptoms. Note the yellow areas to one side of the midveins and the dark green areas directly opposite. Source: California Agriculture journal, October - December 2012, Volume 66, Issue 4.
Regardless of where you live in California, it is time to get familiar with the Asian Citrus Psyllid (ACP).  Since first being found in California in 2008, the Asian citrus psyllid has been spreading throughout California and there are now county-wide quarantines in place in Imperial, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, Tulare and Ventura Counties, with portions of Alameda, Fresno, Kern, Madera, Merced, San Benito, San Joaquin, San Luis Obispo, Santa Clara, and Stanislaus counties also under quarantine.

Continuing Education Opportunity

ACP can carry the disease huanglongbing (HLB), also known as citrus greening which currently has no cure and is fatal for citrus trees. UC Master Gardener volunteers are providing ongoing outreach and education of the public concerning ACP and HLB.  This activity is crucial to saving our citrus and must be expanded throughout the state.

Improve your knowledge of citrus integrated pest management (IPM) and what you can do to help save our citrus through the various training materials, websites and an online course developed by UC Agriculture and Natural Resources experts.

Take the online course for continuing education today.  This self-directed course familiarizes users with the biology and management of ACP and HLB.  At the end of the course, a certificate is provided showing evidence of successful course completion. If asked for a password and login simply enter as a "guest" located under login at the bottom of the screen. This training is available to the public and no login is required. 

Asian citrus psyllid (ACP) adult and nymphs. Source: California Agriculture journal, October - December 2014, Volume 68 number 4.

Online training course:  Asian Citrus Psyllid and the Dreaded Huanglongbing Citrus Disease

It is estimated that 60% of Californians have at least one citrus tree in their yard so HLB could have a devastating effect not only on California agriculture but also on the California residential landscape.  Be part of the prevention effort by staying educated and alert to our local citrus.  Save our citrus!

 

 

 

Sources:
California Department of Food and Agriculture: https://www.cdfa.ca.gov/plant/acp/
University of California ANR: http://ucanr.edu/sites/ACP/
University of California ANR Publication 8205: http://anrcatalog.ucanr.edu/pdf/8205.pdf

Posted on Wednesday, January 20, 2016 at 8:52 AM
  • Author: Lauren Snowden

Holiday Season Brings Poisonous Plants into the Home

Amaryllis plants (Hippeastrum sp.) have toxin primarily in the bulb but also the leaves and stem.
During the holiday season many plants, cut flowers and flowering bulbs are used as decoration and given as gifts.  Many of these items can be poisonous to both humans and pets with long-term negative effects to ones health.

Plant poisoning can range from simple rashes and blisters all the way to organ damage and in severe cases death. Be safe this holiday season by being mindful of what plants and flowers you are either giving, receiving or decorating with.  Common holiday plants that pose a toxic risk are; Amaryllis (bulb portion), Chrysanthemums, Holly (berries), Mistletoe (berries and leaves) and Poinsettia. 

Mum plants (Chrysanthemum sp.) have toxic parts above ground.

Seven simple steps can be taken to help minimize the risk that poisonous or toxic plants cause when brought into the home: 

  1. Know what plants you have in your home and the health risks they pose
  2. Place poisonous plants out of reach of children and pets
  3. Teach children not to put any part of a plant in their mouth
  4. Discard plant leaves and flowers in a safe way so that children and pets cannot get to them
  5. Use protective gloves and clothing when handling plants that may be irritating to the skin
  6. Wash your hands after handling plants
  7. Don't garnish food trays or tables with poisonous plants
    Holly plants (Ilex sp.) have toxic berries.

Signs of poisoning range from dizziness, nausea, vomiting, diarrhea to stomach cramps.  Some plants cause irritation to the skin, mouth and tongue and immediate burning pain. The signs of poisoning may not appear immediately so if you suspect that someone has been poisoned by a plant, telephone your doctor of the Poison Control Center 1(800)222-1222.

If you are advised to go to an emergency room, take the plant or a part of it with you (take more than a single leaf or berry). Take the label, too, if you have it. The correct name can result in the proper treatment if the plant is poisonous. If the plant is not dangerous, knowing the name can prevent needless treatment and worry.

The entire mistletoe plant (Viscum album) is considered toxic.
 

To view a list of safe and toxic plants for humans or pets visit: 
http://ucanr.edu/sites/poisonous_safe_plants/ 

Sources:

UC ANR Safe and Poisonous Plants
California Master Gardener Handbook, Chapter 20 Poisonous Plants 

 

 

Poinsettia plants (Euphorbia pulcherrima) has toxic white sap.

 

 

Posted on Thursday, December 10, 2015 at 2:08 PM
  • Author: Lauren Snowden

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