After a Freeze, What Should a Gardener Do?

After several days of bone-chilling mornings with temperatures dipping into the low-to-mid twenties, should shivering gardeners:

a) remove all plants that look frost-bitten; 

b) prune away all freeze-damaged plant parts;

                   

c) Purchase and plant again this weekend those same varieties of trees, shrubs, perennials and annuals;

                 

d) If it isn't raining, water the garden, even if the plants resemble toast;

            

e) fight the urge to prune and plant by staying indoors, next to the wood stove.

The answers happen to be the easiest to accomplish on a cold weekend: d) and e).

Even if plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

New growth beneath the frosted branches of a geranium.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors. 

The average frost season for Sacramento is about two months, primarily December and January. But temperatures below 32 have been recorded as early as the first week in November; as late as the third week in March.

So, keep the shears in the garage and let the dead portions of the plants protect the understory. It may take until mid-Spring before you see new growth; patience is key before you pick up the pruners.

Make sure your garden and potted plants remain moist. Water gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.

It's dead, Jim.

Some of those dead plants may be summer annuals, such as this impatiens, which took its sweet time to croak. Mornings hovering around 25 degrees can do that to a summer annual. Put them in the compost pile; plant more in the spring, after all danger of frost.

Frosty the Ficus

And what about those plants that have frozen past the point of no return? Should you replace them with the same varieties? That frozen ficus may be Mother Nature's way of telling you: "Hey! This ain't San Diego! Pick outdoor plants that can take colder temperatures!"

Wilting Plants? Check Soil Moisture Before Watering

Improper watering is the number one cause of plant failure. Knowing how wet the soil is at the root level can help you keep your plants healthy. 

Keep in mind: different plants have different watering needs. Learn those needs, then group plants together with similar watering requirements when designing your landscape. The Sunset Western Garden Book is a good source for that information.

Signs of not enough water at the root level of plants: 
Wilted leaves in the morning. Wilted leaves in the afternoon.
Wilted leaves in the evening.
Red-brown margins of leaves.
Premature fall color of leaves.
Growth reduction.
Leaf drop.
Branch dieback.

Signs of too much water (also called aeration deficit) at the root level of plants:
The soil has a foul smell, like rotten eggs.
Soil is a blue-gray color.
Yellowing, wilting and/or dropping of leaves.
Limited new growth.
Small, corky outgrowths on the undersides of leaves.


Be warned, though: sometimes, symptoms of overwatering and underwatering can be the same (such as leaf wilting). And, symptoms of soil water problems may actually be another problem...that was caused by your watering regimen! Root rots, for example, thrive in saturated soils.


Frequent, light watering leads to shallow rooting, increasing the chances of plant problems.

Regarding droopy leaves on a hot afternoon: there are two schools of thought.
One school says plants conserve moisture on a hot afternoon by allowing their leaves to sag.

The other school says: don't believe them. Drooping leaves are usually indicative of a lack of water from the root zone. "Large, thin leaves, common in many of ornamental, annual and vegetable species, do not conserve water," writes Washington State University Horticulture Professor Linda Chalker-Scott. "Tomatoes, zucchini and black-eyed Susans...are not water conservers. Chronic wilting of these and others can eventually cause leaf tip and margin necrosis (or tissue death). It also reduces growth, so that your yield of tomatoes, zucchini and black-eyed Susans will be decreased."
She advises applying a layer of mulch around those plants to help conserve water. 

Also, check the moisture at the root level before watering.
  
To determine the amount of water at the root level:

• A day or two after watering, dig down 8 to 10  inches with a trowel or small shovel, near the drip line (outer canopy) of the plant. Doing this in two or three spots would be more helpful.

• At that depth, grab a handful of the soil. Squeeze that handful. If it is muddy and watery, reduce your watering for plants that require regular (but not frequent) irrigation. If it is so dry you cannot form a clod in your hand (it turns to dust instead), increase your watering (for those plants that require moderate amounts of water).

• If you can form a dirt clod in your hand, yet break it apart with a little effort, that is probably the correct soil moisture for your plant.

• Steve Zien, owner of the Citrus Heights-based organic landscaping consulting service, Living Resources, recommends the use of a soil sampling tube to determine the moisture at root level. "Just press the tube down six to eight inches into the soil after you are done watering," says Zien. "When you bring it back up, the open slot along the side of the tube will let you see if the soil at that depth is wet, moist or dry. Adjust your watering time so that the soil sample is moist, not too wet or dry."

• An easier, but more unreliable way to measure the water content of the soil: purchase an inexpensive (under $10) moisture meter, available at most nurseries. Test its accuracy by putting its probe into a glass of water. If the probe does not read "wet", choose another. Expect it to function for only a year or so.

• Battery operated moisture meter probes may set you back a few more dollars, but in my experience - with proper care (clean them after each use, don't leave them outdoors) - they will last many years.

 

• Extended, infrequent, slowly applied irrigation is the most efficient watering method. Soaker dripline or drip irrigation systems work best. Here in the Central Valley, foothills and Bay Area, run them for 3 to 6 hours at a time, twice a week, in the summer. This is only a guideline to get you started. Adjust that timing to your particular soil type and plants.

• And, don't forget: add more drip emitters and drip lines as the plant grows, especially for trees and shrubs. Make sure to get water to the outer canopy of the plant (and beyond) where the roots travel.

How much water does your lawn need? 

Some tips from the UC Integrated Pest Management Website:


• Avoid planting turf species that require frequent watering, such as bluegrass or ryegrass.
• Design your landscape to minimize water runoff onto hard surfaces and into storm drains.
• To reduce runoff, install non-irrigated buffer areas, which include water-efficient plants or permeable features, next to sidewalks or on slopes.
• Aerate heavy or compacted soils, so water can easily move down to reach grass roots.
• Install an irrigation system that you can adjust to properly water areas of your landscape that have different requirements.
• Water only when your lawn needs it.
• Water requirements vary according to turf species, location, and month of the year.
• Most lawns need water when the top 2 inches of soil have dried out.
• Shady and sunny areas and different soil types will have different water requirements.
• Deeper, less frequent watering is best for most lawns. Water only 2 to 3 times a week.
• Make sure your sprinkler system isn’t producing runoff, especially on slopes. If you see runoff, use shorter watering times and repeat the cycle to allow time for the water to move into the soil.
• Water early in the morning when evaporation and wind are minimal.
• Adjust your watering schedule seasonally, and shut off your irrigation system during rainy weather.


And, the video: How Much Water Do Your Plants Need?

After the Freeze, What should a Gardener Do?

After several days of bone-chilling mornings with temperatures dipping into the low-to-mid twenties, should shivering gardeners:

a) remove all plants that look frost-bitten; 

b) prune away all freeze-damaged plant parts;

                   

c) Purchase and plant again this weekend those same varieties of trees, shrubs, perennials and annuals;

                 

d) water the garden, even if the plants resemble toast;

            

e) fight the urge to prune and plant by staying indoors, next to the wood stove?

The answers happen to be the easiest to accomplish on a cold weekend: d) and e).

Even if plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors. 

The average frost season for Sacramento is about two months, primarily December and January. But temperatures below 32 have been recorded as early as the first week in November; as late as the third week in March.

So, keep the shears in the garage and let the dead portions of the plants protect the understory. It may take until mid-Spring before you see new growth; patience is key before you pick up the pruners.

Make sure your garden and potted plants remain moist. Water
gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.

 

Other frosty garden tips that bear repeating:
• If you still have cold-susceptible potted plants on the porch or patio, move them to a sunny spot indoors or to a west or south-facing outdoor wall.

• Another way to achieve a few degrees of protection: construct a tent around a freeze-threatened plant, especially citrus, using frost blankets or row cover material. Your local nursery will have several products that will do this job. Old bed sheets work well, too.

• The larger sized Christmas lights or a couple of 150-watt light bulbs located in the central area of an orange tree (or any other cold-intolerant shrub) may add two to four degrees Fahrenheit of protection.

• Harvest any citrus fruit that is ripe, especially on the outer
branches.

• Wrap any exposed plastic water pipes; cover outdoor faucets, as well.

• Adjust your pool, spa or pond filtration timers so that they are running when the chance of freezing temperatures is greatest, between 2 and 9 a.m. Moving water is less susceptible to freezing.

• Make sure the backyard birdbath isn't frozen over in the morning.

• Daily fresh water for dogs and cats is also a good morning habit.

And what about those plants that have frozen past the point of
return? Should you replace them with the same varieties? That frozen ficus may be Mother Nature's way of telling you: "Hey! This ain't San Diego! Pick outdoor plants that can take colder temperatures!"

 

From the garden e-mail bag, Rob asks: "A lot of my lantana was burned by the cold weather. Should I trim in winter or wait until spring?"

Lantana is from the tropics, so it is a borderline plant here.
A light frost usually just damages the outer leaves; but a heavy frost or freeze may kill the entire plant. The good news: it may come back to life with new growth from the base, but not until late in spring. In the meantime, do nothing. Those dead branches may be keeping the base alive.

How Much Water Does Your Garden Need?

HOW MUCH WATER DOES YOUR GARDEN NEED???

Improper watering is the number one cause of plant failure. Knowing how wet the soil is where the plant roots are hard at work can help you determine your plants' health. Keep in mind: different plants have different watering needs. Learn those needs, then group plants together with similar watering requirements. The Sunset Western Garden Book is a good source for that information.

To determine the amount of water at the root level:

• A day or two after watering, dig down 8 to 10  inches with a trowel or small shovel, near the drip line (outer canopy) of the plant. Doing this in two or three spots would be more helpful.

• At that depth, grab a handful of the soil. Squeeze that handful. If it is muddy and watery, reduce your watering for plants that require regular (but not frequent) irrigation. If it is so dry you cannot form a clod in your hand (it turns to dust instead), increase your watering (for those plants that require moderate amounts of water).

• If you can form a dirt clod in your hand, yet break it apart with a little effort, that is probably the correct soil moisture for your plant.

• An easier, but more unreliable way to measure the water content of the soil: purchase an inexpensive (under $10) moisture meter (pictured at top). Test its accuracy by putting its probe into a glass of water. If the probe does not read "wet", choose another. Expect it to function for only a year or so.

• Battery operated moisture meters may set you back a few more dollars, but in my experience - with proper care (clean them after each use, don't leave them outdoors) - they will last many years.

• Extended, infrequent, slowly applied irrigation is the most efficient watering method. Soaker hoses or drip irrigation systems work best. Here in the Central Valley, foothills, and Bay Area, run them for 3 to 6 hours at a time, twice a week, in the summer. This is only a guideline to get you started. Adjust that timing to your particular soil type and plants.

• And, don't forget: add more drip emitters and drip lines as the plant grows, especially for trees and shrubs. Make sure to get water to the outer canopy of the plant (and beyond) where the roots travel.


And, the video: How Much Water Do Your Plants Need?