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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Below are five plants you can grow in containers this fall and winter.

   

Arugula

arugulause

 

Delicious peppery taste! Nutritious and good in salads combined with lettuce, mixed in pasta. Fast growing.

Container should be at least 8” deep and 6” in diameter per each arugula plant

Light Requirements
Likes 6 hours of sunlight

Water
Likes to stay moist

Protect from deer with wire or netting

How to harvest
Cut the outer leaves while plant is still growing in a tight rosette. The flavor of arugula will get stronger once they bloom

   

Lettuce

lettuceuse

 

Fresh grown lasts longer and it’s more flavorful. Loose leaf or romaine handle cold better. Fast growing.

Container You should have a medium sized container. 6-8″ inches between young plants

Light Requirements
Partial shade is okay

Water
Regular water

Protect from deer They really like lettuce.  Protect with wire or netting

Frost
Lettuce is more sensitive to frost.  Buy fabric cover to protect it.

How to harvest
Cut the outer leaves

   

Kale

kalecontuse

 

Highly nutritious and tasty sauteed lightly in garlic and olive oil. Many people love it raw. They are also a cold-hardy plant.

Container should be at least 12″ diameter

Light Requirements
Likes full sun but will tolerate part shade

Water
Likes regular watering

Protect from deer with wire or netting

How to harvest
Pick the oldest leaves from the lowest section of the plants

   

Garlic

garlicuse

 

Plant garlic from bulbs in your nursery.  Garlic makes everything taste better and some swear by it as a health remedy.  A few days before planting, break apart cloves from bulb and keep the papery husk on each individual clove.

Container
Bulbs should be planted 2-3″ deep and have room for roots to grow.  So, container must be at least 12″ wide and 18″ deep and allow 6″ between cloves.

Light Requirements
Likes full sun

Water
Likes moisture. But, make sure soil drains well because bulbs can rot

Protect from deer with wire or netting

How to harvest
Pick the oldest leaves from the lowest section of the plants

   

Mustard Greens

mustard

 

Great sauteed are in soups or stews. Spicy leaves cook well with strong ingredients like onion and garlic. Smaller, milder ones are good in salads and stir fries.  They are also a cold-hardy plant.  Not as cold hearty as kale but they can tolerate a light frost.

Container should be at least 12″ diameter. Plant 3-5″ apart (seedlings). Thin seedlings once they reach 3-4″ high

Light Requirements
Likes full sun

Water
Whenever the top 2″ of soil feels dry

Protect from deer with wire or netting

How to harvest
The larger the leaf, the stronger the flavor will be

 

 
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Rain garden Graphic from Nature Conservancy

Indicators for the Northern California rainy season are uncertain. Although we’ve had heavy rain early in the season, and more is predicted in the next week, none of the long range weather modeling has been conclusive.  We can only hope for a wet winter. 

You can bet that there will be high winds, and heavy downpours this winter.  And, it can do damage and cause flooding if your drainage is not prepared.

What is drainage and why is it important?
When there is heavy rain, water infiltrates into the soil. Once soil becomes saturated and no more water can be absorbed, it begins to pool on the surface.

If the period of saturation is prolonged water will continue to flow into the deeper layers of soil damaging the roots of your plants.

Drainage is a system of removing excess water either from the ground surface or the rootzone.

Surface drainage is removal of water the ground surface

Subsurface drainage is removal of water from the root zone

Your drainage system will protect your building or house from costly water damage and plants from root damage. Have your drainage checked before winter.  Below we drill deeper into methods of drainage.

Soil Drainage

Most plants need soil that drains well.  That refers to soil whose texture is loose enough to allow water to pass through.  The characteristics of clay soil, which is common in the San Francisco Bay Area, are unfortunately, is the opposite. Compacted soil has the same problem. Heavy rain can cause plant decline and rot.  You can observe this problem by its smell – foul odors. By sight – grey, red or orange spots and insects. 

The solution to soil draining problems:
Organic amendments will improve soil structure.  Inorganic amendments like sand can also be added along with other components.  It is best to rely on a professional who can advise the right combination of ingredients.  2” of mulch also can help at least 2” of mulch over the landscaped area around your house or building.  It will help your property absorb rain more safely in addition to cutting down on erosion or immediate runoff.

Grading To Correct Slope

The ground should slope away from your home or building instead of toward it.  Water runs more quickly down a slope, particularly a slope of clay soil.  The soil surface should not be above your foundation.

The solution grading issues:
There are a number of strategies depending on the property. Trimming back landscape overgrowth on a hillside or low lying area is one.  Grading may be required.  This involves directing surface water to the lowest spot on the property which will empty into a drainage ditch, catch basin or well.

Regular Testing of Landscape Drains*

Visually inspect.  Make sure they are all functioning. Leaves, roots and dirt and other matter can easily block a drain causing water to back up.  Storm water runoff from surfaces such as roofs, driveways and patios should be directed into a collection system to avoid flooding.  This will damage plant roots.

If your building or home does not have gutters or drains consider having them installed.

Proper Retaining Walls

If your property is on a slope a retaining wall could be essential erosion protection.  Make sure to hire a knowledgeable professional to understands its proper construction and drainage as well.

*Types of drainage systems

Catch Basin
A surface drain.  It collects and traps debris in storm drains and prevents it from entering drainage pipes.  
 
Channel Drains
A surface drain. Long narrow strips used between main structures and paving at the edge of a patio or deck
 
French Drains
For patios, decks or walkways so that water is sloped toward them or into landscape beds. Drain covers are usually made of metal or stone.
 
Swales
Shallow trench that carries runoff away from building to municipal drains or ditches.
 
Rain Gardens
Shallow, bowl shaped depressions that are densely planted with flowers, grasses and other plant material. Rain gardens will collect runoff from gutters, roofs, decks and other surfaces. Water percolates gradually into the soil and is absorbed by the plants. Rain gardens also help prevent ground and surface** water pollution.
 

 

 

 

 

budgetart

If you are a Property Manager, you are likely knee-deep in budget season

Remember that landscaping can increase the value of a house from 5% to 12.7%.  On a $400,000 home 5.5% is $22,000; 12.7% adds $50,800.*  Conversely, a degraded or disorganized collection of plants detracts from a home or commercial building’s value.  Bob Vila says that the biggest mistake homeowners make is a lack of a coherent plan. Similar for commercial properties and residential communities.

With the long term in mind, make sure you have these 4 categories covered in your landscape budget for 2017.

Landscape management:

  • Allow for materials cost increases for items such plants, including annual color; mulch.
  • Mulch replenishment is important. It has a neat appearance and helps soil hold water.
  • Annual color replacement
  • Allowance for IPM (Integrated Pest Management) treatments
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Irrigation upgrades and repairs**

  • An irrigation system installed more than ten years ago may be wasting water and costing you money. Ensuring efficiency may mean replacing and repairing.
  • Smart (or weather based) irrigation controllers can also save up to 30% off your water bill.
  • Converting from spray to drip is something to consider for your budget.
  • State of the art precision spray nozzles can improve spray irrigation efficiency and save water too.

Large Tree Care

  • Routine pruning and fertilization are important for the health of your trees – an important part of your asset. Older trees may need more maintenance.  With proper care your trees will last many years.
  • A tree care plan will alleviate the stress of emergency tree work needs.

Landscape Improvements**

  • Turf care includes aeration and soil building or possibly overseeding.
  • Because of California’s ongoing drought and San Francisco Bay Area restrictions, you may consider converting turf to drought tolerant plants.
  • Consider converting annual color to more permanent perennial plant material.
  • The useful lifespan for large shrubs or small trees is approximately 7 to 10 years. When plants are past their useful lifespan they should be replaced with new plant material.

* Source: Hortculturalist Alex Niemiera of Virginia Tech researched the impact of landscaping on the value of a home. 

**Note: Depending on your location there could still be rebates available from your water district.

WaterEducationGraphic

Winner of Sonoma County Water Awareness Contest for 3rd and 4th Graders

Simple Irrigation Fixes That Can Save $$$$

Consider this first: 80% of plant problems are due to over-watering.  (Source Sunset Magazine)

Gardeners’ Guild saved a residential community client 53% off their water bill by rigorous monitoring of their system and simple repairs.

  • Fixing Irrigation Leaks and Breaks*
  • Capping irrigation in places that didn’t require watering
  • Consistent monitoring

Make sure you are not wasting water due to leaks!  Here are some facts about leaks:

  • Drip irrigation is efficient when it is not leaky.  If an emitter gets chopped, tubing can get punctured and valves can get stuck open.
  • A system that has a leak of 1/32nd of an inch in diameter (about the thickness of a dime) can waste about 6,300 gallons of water per month.
  • Check your garden hose for leaks at its connection to the spigot.  It it leaks while you run your hose, replace the hose washer to ensure a tight connection.

If you have a high water bill and suspect it is due to a leak, consult with certified irrigation professionals like Gardeners’ Guild.  We have a team of experts who know precisely where to look.  Whether it’s your residence or a commercial building call us even if you have a question.

Irrigation improvements will also make a difference

  • For ground cover and shrubs – convert from spray irrigation to drip.
  • For turfgrass – convert to high efficiency nozzles.  Turn your standard spray head into a precision device.  It will reduce runoff and save you money.
  • Automatic rain shutoff device; called a rain sensor, will shut off your irrigation system when it senses a specified amount of rain has fallen.  It is simple and inexpensive.
  • Smart or weather based irrigation controllers will save you upwards of 30% off your water bill. They calculate plant water requirements using on site or remote weather stations.

Cultural Practices

  • Remove all or some of your turfgrass and replace with drought tolerant plants or natives.
  • Is your lawn compacted?  This impedes the soil from absorbing water.  Aeration and dethatching will reduce the amount of water your lawn needs.
  • You can mow less.  Allow it to grow out as seasonally appropriate.  It will lessen heat exposure to soil, producing deeper roots and providing a larger soil reservoir to draw from.
  • Mulch your planter beds.  This will increase their water holding capacity.
  • Organic products make your soil healthier and it will hold more water.

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