Why your weeds keep coming back

Have you noticed an abundant crop of weeds this spring?  One reason – the heavy rains of last fall and winter may have awakened long-dormant seeds.  Does it feel like the long rainy winter just erased all the backbreaking work you did last year?  Our guide to weeds includes the why what and how of managing weeds. 
Plus our guide to weeds is downloadable.  See link below.

Why do they reappear?

  • Weeds produce thousands of seeds.  Those seeds are stubborn and can be viable for years, even decades.
  • They are transported by weather, especially wind. Also by animals, humans, and water. Mulches and soil can also harbor weed seeds.
  • Even after weeding, their seeds will remain in the soil and may be dormant for years.
  • Perennial seeds are the hardiest.  Their roots are alive for many years and harder to kill than annual weeds.
  • An example of a perennial weed is a dandelion.  Just one dandelion puffball carries as many as 100 seeds!

Understanding is the key to managing weeds

They are tough and relentless. Weeds can thrive in the most unsavory environmental conditions. Drought, fire and even herbicide applications don’t kill all weeds.  And, they will outcompete with desired plants for sunlight, water, nutrients, and space. 

Weeds offer some benefits

  • Protect bare soil from erosion.
  • Improve the soil by imparting organic matter.
  • Absorb carbon dioxide from the atmosphere.
  • Can provide habitat for birds, worms, and beneficial insects.
  • And – some have powerful medicinal properties (and are edible)

Weeds are a problem when

  • They overpower desired plants and deplete the soil of nutrients and moisture.
  • Their unattractive appearance, texture, color and growth habit detracts from your garden or landscape.
  • They harbor disease-carrying insects that spread to desired plants.
  • Poisonous weeds can be dangerous to you and your pets.
  • Invasive weeds take over your garden in a single growing season.

Two types of weeds – what makes them different

Annual Weeds
Warm weather annual weeds grow only from seeds every spring.  Cool weather weeds germinate in late summer or fall. Their roots are shallow as compared to perennial weeds (see below). For this reason, they are easier to pull.  Some die out after flowering.

Perennial Weeds
These weeds reproduce year after year from roots and seeds.  Because of their tenacious roots and seeds that can live for years, they are much more difficult to control.  Two common perennial weeds in the San Francisco Bay area are dandelions and oxalis.

Tips for Managing Weeds

The harsh truth is that you can never completely eliminate weeds, but effective management will help control them. 
Your first step is prevention.

Tips on Weed Prevention

Plant Choices
The right plant in the right place sounds simple but makes all the difference.  Healthy vigorous plants have the best chance of out-competing weeds.  
Healthy Soil
Make sure that plants are healthy by feeding the soil with organic products including mulch and compost.
Mulching and Sheet Mulching
Mulch keeps the soil cool and moist.  It deprives weeds of light.  Organic mulches enhance soil structure and host insects can devour weeds.  Sheet mulching is layering of cardboard, newsletter or fabric.  It serves as a weed barrier.
Proper irrigation is critical
We recommend drip because the water goes directly to the root of the plant, not in between them. Spray irrigation can encourage weed growth.  
Pre-emergent Herbicides
There are products that range from natural to chemicals whose purpose is to control the germination of weed seeds. This product will not impact weeds that have already grown.  An herbicide is a barrier so it needs to thoroughly cover an area for maximum effectiveness.

 

How to get rid of them?

Gardeners’ Guild’s philosophy is to use the least toxic practices. We recommend a combination of prevention, mechanical, biological, and chemical means only when necessary.  

Hand Pulling
This works best when weeds are small and before they flower.  Once they flower, seeds will be spread.
String Trimming
This works best for annual weeds.  It is used for the top growth control of broadleaf weeds.
Mowing
For a heavily weeded area, mowing helps prevent broadleaf weed seeds from spreading but cutting off flower heads.
Flaming
Less effective for deep-rooted (perennial) weeds. This method requires a propane burner which burns cell walls of the seeds.
Post-emergent Herbicides
Their purpose is to kill weeds once they appear. This product will either target foliage and/or weed roots. Take precautions when using and be aware of any community regulations against them. 

 

Weed Types Common to SF Bay area

Below is a list of common San Francisco Bay area weeds.  Some are invasive and fire hazards.  Invasive weeds will damage our ecosystems by displacing native species, increase fire and flood danger and consume valuable water.
 
Ice plants – Invasive
They compete with native plants. Seeds are carried from landscape settings to natural areas. Pieces of the plant can be washed into storm drains. They grow in natural areas and along freeways. Remove by hand pulling, mechanical methods.  Glyphosate is effective but only as a last resort.
Oxalis/Wood Sorrel
Grows in lawns; flower beds.  Blooms in spring. Spreads rapidly by their many persistent bulbs. Very competitive. Remove root bulbs before they bloom.  Sheet mulching or post-emergent treatments are used.
Dandelion
Perennial. Seeds spread in wind. Leaches nutrients from the soil of desired plants. Prevention is key. Hand weeding and fabric mulching can work.  Herbicides if necessary.
Periwinkle/Vinca Major – Invasive
Their aggressive stems root wherever they touch the soil.  Spreads rapidly in shady creeks, drainage areas and chokes native plants. Vinca minor is okay.  Removal by hand pulling.  Rake the area to loosen the soil. Or, brushcut and cover area with cardboard for at least a year.
Licorice Plants – Invasive
Seeds spread by wind.  Spreading branches root wherever they make contact.  They can and do displace native plants in coastal areas. Hand pulling is effective for small infestations.  for larger areas, herbicides are used.
English Ivy – Invasive
Distinguishing them from less invasive ivy is difficult.  Invasive ivy will smother understory vegetation, wrap around trees and harbor non-native rats and snails.  Removal – wear protective clothing. Dig down 8-10 feet should get at their roots. Dispose of plants. A large expanse of ivy can be rolled like a carpet.
 

Download our report on Weed Management

 

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Water saving trends, tools and tips for your SF Bay Area landscape

Irrigation technology is becoming more efficient.
Our post lists trends and tips you can use to irrigation more efficiently. 

Smart Irrigation Controller Trends
What you need to know about trends in Smart Irrigation Controllers

It’s about accessibility!
And, cloud storage.
Controlling your system on any device anywhere.  All you need is an app.
Access using your cell service or WiFi.

Remote access on your device enables you to

Program the controller.
Revise schedules; start and stop.
Manage water budgets.
They can detect leaks. 
User will receive real time notifications, saving precious time and water for homeowners and Property Managers.

Programming a Smart Irrigation Controller is more complex
Get training or hire a professional

To fully utilize their water saving capability a ton of data needs to be entered correctly.
For example: soil type, slope information, sun or shade, plant types and type of irrigation.

Weather data is accessed via the web or local weather stations.
Historical weather data can help with a watering schedule and it can serve as a back up if there is an interruption in service.

See our previous blog for rebate information.  Depending on the district, there might still be rebates for purchasing smart irrigation controllers.

Irrigation Tips

Practices that will save you water

Hydrozone your plants
It just means grouping your plants by their water needs.  Your drought tolerant plants are mixed in with water loving plants neither will be happy.  You will either have crispy leaves or root rot.
Example: seasonal color beds have different water needs from turf areas.  They should have separate valves.

Pay attention to the water needs of maturing plants
Their water needs may change as they grow.

Manage your irrigation system’s water pressure
Adjust as needed.  An example: too much pressure will cause runoff and waste water. 
Older sprinkler nozzles may need replacing.  See below on trends and tools for irrigation.

Irrigation Trends & Tools

Spray Irrigation Trends | Pros & Cons

It is designed to irrigate with a high volume of water using spray heads.
It is best for large turf areas that are wide and flat.

Pros

It is easy to repair.
Spray patterns are adjustable.
Water is distributed uniformly.

Cons

They waste water due to evaporation and runoff.
Because water is applied to foliage – there is potential of plant disease.
Winds will reduce its efficiency of application.
They are only 50-70 percent effective.


Trends
High efficiency nozzles can reduce water use.
We recommend them when appropriate.  “They require longer irrigation run times.
“Make sure you are aware of your plant water needs”, says Paul Swanson, thirty-year veteran of GGI and the company’s Director of Business Development.

Drip Irrigation Trends| Pros and Cons

For plants other than turf, drip is most efficient.  Over 90 percent. 
Water is released slowly and directly into the soil from its emitters.

Pros

The water goes directly to the base of the plant.
It costs less to install, than a sprinkler system.
Water is applied slowly.  Particularly good for slopes.  It minimizes the chance of runoff.
Lower water use; less waste.
Less contact with foliage. Less chance of disease.

Cons

Because the tubing is below ground, repairs are more complicated.
It requires regular maintenance to ensure plant health.  This is the only way to confirm that the system is releasing sufficient water.
Tubing can become blocked so periodic flushing is a necessary part of maintenance.

Conclusion

Not only does California have to plan for potential droughts, but the reality is that water prices will continue to rise.
A study contracted by the Institute for Public Utilities states that water and sewer rates are growing by an average of 7 percent a year.  This exceeds income growth.  The reason – customer revenues are no longer sufficient for utilities to recoup rising operating costs.

Sources

The irrigation experts at Gardeners’ Guild
Irrigation Association
Love your landscape
Turf Magazine

 

 

 

 

 

About Bamboo

Adorning the perimeter of many commercial buildings, the willowy Bamboo stands, in containers and planter beds, providing screens and landscape focal points. Its reputation as a renewable resource for flooring to furniture and even fabric, make it emblematic of the sustainability movement.

We maintain several sites in San Francisco with Bamboo plants and we appreciate their beauty, first-hand. They are finicky though, and need to be planted in just the right micro-climate. 

Because of its heightened interest we thought you might be interested to know more about them. Each Bamboo will have slightly different characteristics so in the interest of brevity we are providing general tips that apply to most Bamboo plants.

Types of Bamboo

There are numerous varieties of Bamboo.  One clarification – Lucky Bamboo is actually not a Bamboo.  It comes from the Dracaena family. 

Bamboo grows by spreading horizontally through “rhizomes”.  Rhizomes are modified stems running underground horizontally.  They represent a part of plant production and also store nutrients.

Below to the right is a simple illustration that points out the main parts of a Bamboo plant: the Culm and Rhizome.

 

Clumping Bamboo

One of the challenges of Bamboo is that it can be invasive.  The benefit of Clumping Bamboo is that its rhizomes do not spread so rapidly.  They are also slightly more drought tolerant.

  

The Parts of a Bamboo

Running Bamboo

They have long Rhizomes which enable them to spread rapidly. This type of Bamboo is considered invasive.

   

The Best Environment for Most Bamboo

  • Full sun. That means 5 hours of sun.
  • Well draining soil is preferred. Amend clay soils to improve drainage.
  • Water once or twice a week for a young Bamboo.
  • After that time once per week or less should be sufficient
  • Bamboo does not tolerate soil that is too saturated.  Roots that sit in water can rot.

 

 

Well Drained Soil

What Stresses a Bamboo?

  • Abundant sun combined with dry wind can stunt the growth of a Bamboo and cause winter burn.
  • Frost can also damage a Bamboo
  • Over-watered Bamboos can be excess yellowing foliage, rotting new canes
  • Too much sun and heat
  • Lack of water their leaves will curl in a “v” shape
 

Stressed Bamboo

Planting Bamboo in Containers

The larger container the better.  One source suggests 18”x18” and 18” deep box is the smallest size container they recommend.  Your container should be wider than it is tall.

Potting soil dries out more quickly and it needs to be moist (not wet).  Make sure your container has drainage so the plant is not sitting in water.

 

About Bamboo Maintenance

  • Bamboo is dormant in the winter.
  • Best time to fertilize is spring and summer.
  • They need occasional pruning and thinning.
  • Once any part of a Bamboo is cut, it will not grow back.
  • Bamboo leaf litter is actually good for the soil. Although in urban environments it may make the base of the plant look messy.
  • Because of how the Bamboo grows it will usually have a mixture of new and dying or dead leaves.  This can be frustrating for their owners. Some varieties can shed as much 30% of their leaves at a time.
 

This confirms what we expected after a ferocious rainy season that wreaked havoc throughout much the state. 

Key facts:

  • Just one year ago only 5% of the state was drought free
  • Sierra snowpack stands at 179% of its historic average (the biggest in 22 years)
  • San Joaquin Valley and most of Southern California remains in a “moderate drought”.
  • Much of Santa Barbara and Ventura county areas is in severe drought or extreme drought. Although that statistic is down from 2016.

In case you want to know where your water comes a KQED website has an interactive map.  Check it out.

Do you want to know where your water comes from?

Left: Map of 2015
Right: Map of 2017

The list below give you an in depth look at how full our reservoirs are

Reservoir

Status

Serves

Note

San Pablo Creek

130%*

East Bay

Also Briones, Lake Chabot, Lafayette -all full.

San Leandro Creek

127%*

East Bay

 

Lake Mendocino

109%

Northbay

 

Lake Sonoma

100+%

Northbay

 

Marin Reservoirs

100%

MMWD

 

San Andreas Creek

129%*

SF and Peninsula

 

Crystal Springs

127%*

 SF and Peninsula

 

*based on 2017 average percentage capacity

Felicia Marcus, Chair of the State Water Board has expressed relief that water conditions have improved so dramatically, but state policy makers remain cautious.  They voted to continue with mild drought rules and re-evaluate in May.  We will know more about any irrigation regulations by that time.  And, water conservation will likely to be an important issue.

At this time:

Water agencies are still required to report use each month

Wasteful practices such as hosing off pavements and use of hoses without nozzles remain banned.

Sources for this article: San Jose Mercury News, NOAA, KQED.

 

What’s new in landscape and gardening?

Every year there are numerous reports on the latest trends in plants, hardscape, irrigation and even color. From technology to outdoor living. Designers, Landscape Architects and Green Industry pundits weigh in on what’s hot. 

There are several sources for this article. The people at Gardeners’ Guild have chimed in on the latest wrinkle. I’ve combed through Garden Design Magazine, NALP (National Association for Landscape Professionals), ASLA (American Society of Landscape Architects) and irrigation experts. 

According to some experts, Millennials are driving some of these trends.  See below.

More Local Sourcing

Using native plants is a trend that has been building over the years. Some landscape designers see the market’s interest in natives morphing to endemic plants – those which are native to a particular ecosystem.

One example – is a project we completed for U.C. Berkeley in 2016.  It was the restoration of Strawberry Creek.  The specifications required locally sourced plants and mulch. They had to be native plants grown in the Strawberry Canyon area, the location of the project.

Note: I encourage you to visit Strawberry Canyon. It is a marvel – a quiet oasis of nature sandwiched between a highly caffeinated college campus.

More building materials are being sourced locally. A reason for the increased popularity of local sourcing can be traced to climate change. Its geographic impacts and the ensuing regulation on say, the use of chemicals, water and the like are, in part, driving the preference of locally sourcing.

The reasons are practical. Reduced use of fossil fuel to transport them.

Strawberry Creek, U.C. Berkeley

 

Natural Products – With One Exception

There is a gradual shift away from the use of concrete toward natural and materials. Wood, brick, slate, gravel, pea stone and natural stone are popular. Increasingly, green materials are being used for retaining walls, fencing, decking, walkways and outdoor kitchens.
ASLA says “Nature will continue to play an important role in landscape architecture and we as practitioners will continue to be inspired and create designs that emulate and mimic(bio-mimicry) nature. An increasing trend will be to use the messiness and ephemerality of nature in a structured manner to create beautiful landscapes.”

The exception – there is a trend toward the use of artificial turf. Technology continues to innovate a product that looks and feels more like grass. Could they also invent the smell of fresh mowed grass?

 

 
 

Urban Gardening

One type of urban gardening trend that Gardeners’ Guild has noticed is the increased support for urban projects that provide affordable housing, gardens providing food for local residents and restoration projects in low-income urban areas.

ASLA says (American Society of Landscape Architects) “As densities increase in cities we will see larger scale projects that will attempt to service the needs of increasing populations (housing, transport, social, green space, job creation) at a local level.”

San Francisco has a number of projects designed to improve public space. Among them is the Green Benefits District. A quote from their mission statement: “to clean, maintain, enhance, and expand open spaces, parks, plazas, parklets, gardens, sidewalk greening and the Public Realm in general in the Dogpatch and Northwest Potrero Hill neighborhoods”. There are a host of other projects aimed at revitalizing blighted areas such as the Tenderloin.  Gardeners’ Guild did some projects for the Green Benefits District.

Urban Tilth, Richmond is another example. It’s an ambitious non-profit dedicated to improving the health of its community. Their website says: “We farm, feed, forage, teach, train, build community, employ, and give back. We help our community grow our own food;” As part of 2015 Earth Day, GGI helped Urban Tilth plant a  vegetable garden at Verde Elementary School, Richmond.

Container gardening is exploding.  Urban dwellers with limited space see the low maintenance advantages of container plantings. A recent study by Harris Poll found that millennials are embracing edible gardening. Of the 6 million new people who took up gardening, 5 million of them were millennials. Their home gardening interests gravitate toward microgreens, medicinal herbs and herbs they can use in cooking.


 

Interior Plant Trends

Garden Design Magazine forecasts a renewed interest in interior plants for 2017. They say, “Just as bell bottoms are reappearing on runways, a 1970s-style fascination with houseplants is back. Millennials could have something to do with this.

Living walls for commercial buildings remains popular. They come in all sizes including a plethora modular units that can be installed like wall art. A heightened interest in plants for the office may have to do with the needs of younger workers for a healthier work environment. The extensive research about interior plants’ benefits such as air filtering as well as productivity enhancement is now widely available and posted. Plants both in the home and office is a trend that will continue to proliferate.

Irrigation

Brian O’Hara our Irrigation Manager, has noticed an uptick in the choices of add-on technology or upgrade kits that can convert a conventional controller into a “smart” controller*. This is a budget friendly option.

Smart controller technology continues to evolve. With more sophisticated cellular communication and the cloud all the onsite data can be shared with the operator. It has become a two-way wireless communications giving operators the ability to control an unlimited number of stations and flow sensors from a central remote location.

Moreover, they can be programmed and monitored by smart phone. Some include flow sensors that will text a contractor if they detect a leak in the system.

*About Smart controllers: They use weather and on-site local data sensing tools to optimize your water use.