- Author: Help Desk Team
Note: This was originally published in the Contra Costa Times.
Q: I like to decorate my home at the holidays with poinsettias and other holiday plants, but they don't last very long. Can I get my holiday plants to live through the holidays or even longer? Is it possible to get poinsettias to re-bloom?
A: Plants are popular gifts and decorations around the holidays. With proper care, they can last several weeks, and some can live for years. Here are some general guidelines for several popular holiday plants.
Poinsettia (Euphorbia pulcherrima):
These colorful plants can last many weeks if cared for properly. The “blooms” are actually bracts, a type of leaf. Put them in bright indoor light, near a south, east, or west-facing window. Keep away from drafts, heating or air conditioning ducts. Keep the soil uniformly moist but not wet. Never let the plant sit in water.
It's difficult to rebloom a poinsettia and it's unlikely to look as good as when you brought it home, even if you do get it to rebloom. Poinsettias are quite picky, and they need a precise regimen of the right light, moisture, humidity, temperature, food, and pruning to rebloom. They also need absolute darkness from 5 PM to 8 AM every night, from the first week of October until Thanksgiving. It's probably a better use of your time and effort to throw the plant on the compost heap when it no longer looks good and get a new one the following year. That way, you can enjoy the wide variety of colors developed in the past few years. If you must have rebloom, detailed instructions are at: https://ucanr.edu/sites/hdnmastergardeners/Resources_for_Home_Gardeners/Houseplants/Poinsettias/
Christmas Cactus (Schlumbergera x buckleyi):
In terms of easy care, this plant is just about the polar opposite of the poinsettia. It's not fussy about its surroundings and re-blooms readily. The Christmas cactus is long lived and easily propagated from cuttings. Put it in bright but not direct light, let it dry out between waterings, and never let it sit in water. Christmas cactus can spend the warmer months outdoors in a sheltered location. Feed monthly with a diluted water-soluble fertilizer during spring and summer. Withhold fertilizer when the plant is setting buds and resume feeding after flowering. If exposed to sudden temperature changes Christmas cactus sometimes drop their buds, so keep them away from frequently opened doors and out of cold drafts. After blooming, prune the plant lightly to stimulate re-flowering. For more about growing these colorful succulents, please see: https://anrcatalog.ucanr.edu/pdf/8114.pdf
Living Christmas Trees:
These have become more popular as people become increasingly reluctant to cut fresh trees and deal with the disposal issues. Keep your living Christmas tree indoors for the shortest possible time—a week to ten days at the most—and then plant it properly.
Choosing the right tree is essential. A wide range of dwarf varieties are available: yews, junipers, arborvitae, holly, and many conifers. Non-traditional choices abound, too. Consider small palms, potted citrus, laurels, olive trees, and other varieties that are useful, attractive, and could even be used in successive years if kept in a container. Even rosemary plants, which can be pruned into tree shapes, have become popular and transplant easily to outdoor locations. Consider the mature size and growth habit of whatever plant you get and choose a variety that grows well in your area. Don't pick the largest plant available; select one that is smaller in proportion to its rootball or container.
Store the tree in a cool area where it will be protected from wind, freezing, and direct sunlight. Make sure the rootball doesn't dry out. You can spray the tree with an anti-transpirant to help protect it from drying out, but even if you do this, check the soil frequently, water as needed and don't let it sit in water. Bring it indoors as late as possible and place it away from radiators, heater vents, and fireplaces. A cool room is best. Decorate it with lights that don't give off heat.
After the holiday, move the plant back outdoors to its sheltered location and let it get used to outdoor temperatures again before planting. Plant the tree as soon as weather allows. You can find information on planting trees at: https://anrcatalog.ucanr.edu/pdf/8046.pdf
Until the tree's root system has grown into the surrounding soil, it will need frequent but light irrigation. After establishment, the watering schedule can be adjusted to deeper but less frequent watering at the tree's dripline.
Note: The next post will be a more in-depth explanation of planting live holiday trees into the landscape. Stay tuned.
Help Desk of the UC Master Gardeners of Contra Costa County (EM)
- Author: Help Desk Team
To explain seasonal changes, the ancient Greeks told the story of Persephone, goddess of the Spring, who was abducted by Hades and taken to the underworld. Her mother Demeter, goddess of Agriculture, was filled with grief and neglected the earth, creating a famine. Zeus interceded with Hades and negotiated Persephone's return. However, since she had eaten four pomegranate seeds, she has to stay in the underworld for four months each year. During that time Demeter mourns her daughter's absence, causing the earth to enter a period of dormancy when nothing grows until Persephone's return.
This mythological story serves as an allegory for the seasonal changes we see in nature, particularly the transition between growth and dormancy in plants. Today you may still hear the time of winter dormancy referred to as the Persephone Period. In his book The Winter Harvest Handbook, Eliot Coleman describes the Persephone Period as the time of year which begins when daylight falls below 10 hours per day and ends when it rises back above 10 hours. Because most plants need more than 10 hours of daily sunlight for growth, we can use this concept as a guideline to help us know when to plant and harvest as we transition into the winter months.
To find out the local dates of the Persephone Period in Contra Costa, we used the tool developed by the Naval Observatory: (https://aa.usno.navy.mil/data/Dur_OneYear). This year the Persephone period in Contra Costa starts on November 20 and runs through January 22. Between those dates our gardens will be largely dormant. Plant growth slows down or in some species halts completely as the plants seek to conserve energy for the chilly months ahead.
The secret to healthier plants and larger harvests is to work around these dates. For your winter garden, time the planting of cold-hardy vegetables (leafy greens like kale, spinach and Swiss chard, or root vegetables like carrots, turnips and parsnips) to give them ample time to establish before the temperatures get too low. If you plan to grow from seedlings, knowing the dates of the Persephone Period will help you decide when to sow. A rule of thumb is to seed your plants so they are about 75% mature by the time you enter the Persephone Period, which means starting your seedlings between mid-August and mid-September. This timing will allow them to take advantage of the daylight and warmth to reach maturity by mid-November.
This year it may be too late for you to use the Persephone Period to plan your winter garden. But you can still use the end of the Persephone Period in late January to remind you it's time to plant seeds as your garden begins to return to life.
Help Desk of the UC Master Gardeners of Contra Costa County (RDH)
- Author: Help Desk Team
Note: This was originally published in the Contra Costa Times.
Q: I have a lot of mistletoe in my street tree, which is some sort of ash, I think. Is it a problem and if so, how do I get rid of it?
A: Broadleaf mistletoe is an evergreen parasitic plant that grows on a number of landscape trees in California and can be readily observed on deciduous trees once the leaves have fallen. Modesto ash is especially susceptible to mistletoe infestations. As a parasite it absorbs both water and mineral nutrients from its host trees. Healthy trees can tolerate a few branch infections, but individual branches may be weakened or sometimes killed. Heavily infested trees may be reduced in vigor, stunted, or even killed, especially if they are stressed by other problems such as drought or disease.
The Mistletoe Lifecycle:
Mistletoe is either female (produce berries) or male (produce only pollen). The berries of the female are small, sticky, and whitish. Birds feed on and digest the pulp of the berries and excrete the living seeds which stick to any tree branch on which they land. After the seed germinates, it grows through the bark and into the tree's water- conducting tissues where rootlike structures called haustoria develop. These haustoria gradually extend up and down within the branch as the mistletoe grows, and for that reason if you simply remove the visible portion of the mistletoe, it will often resprout.
Controlling Mistletoe:
The most effective way to control mistletoe and prevent its spread is to prune out infested tree branches. Remove branches at their point of origin on the main trunk or back to a large lateral branch and cut at least one foot below the point of mistletoe attachment. Mistletoe infecting the trunk or a main branch where it cannot be pruned may be controlled by cutting off the mistletoe flush with the limb or trunk. You must then wrap the area with a few layers of black polyethylene to exclude light. Use twine or tape to secure the plastic to the limb, but do not wrap it too tightly or the branch may be damaged. Broadleaf mistletoe requires light and will die within a couple of years without it. It may be necessary to repeat this treatment.
Harvesting for the Holidays:
Simply cutting the mistletoe out of an infested tree each winter, even without wrapping, is better than doing nothing at all. Even though the parasite will grow back, spread is reduced because broadleaf mistletoe must be several years old before it can bloom and produce seed. Time your pruning right and you will have plenty of mistletoe for the holidays.
For More Information:
For more information on mistletoe and its management, the University of California has a free publication located at: https://ipm.ucanr.edu/PMG/PESTNOTES/pn7437.html
Help Desk of the UC Master Gardeners of Contra Costa County (EDC)
- Author: Help Desk Team
Garlic (Allium sativum) is loved and respected around the world as a symbol of protection and luck. It is thought to impart strength and endurance and is prized as a natural medicinal remedy with antibacterial, antiviral and antifungal properties. Impressive for such a humble vegetable.
Garlic is best planted in the fall for the largest bulb size at harvest. In USDA growing Zones 9 and 10, aim to get your garlic in the ground 6 weeks before the first frost. For much of Contra Costa County, this will be mid to late October. Bulb formation will begin in the spring as the daylight hours increase.
Refer to our previous blog post for an explanation of hardneck and softneck garlic and selecting seed garlic for the home garden. https://ccmg.ucanr.edu/our-blog/?blogpost=60828&blogasset=12496
Site selection
Find a convenient location with access to water and select a planting site which is level for consistent irrigation. Garlic takes 6 to 9 months to mature so the bed you select will not be available for another crop from October to June. Garlic does best in full sun (a minimum of 6 hours of sun a day). Clear all weeds from the bed and surrounding area. Weeds deprive the garlic of nutrients and water and can harbor many of the pests which are attracted to garlic.
Prepare the soil
Garlic does well in a wide range of soils, but the soil needs good drainage. Damp soil surfaces encourage snails, slugs, and root diseases. Much of our soil in Contra Costa County is heavy clay, so amendments are often added to give the clay soil a better structure. Adding organic matter such as compost, manure and leaf mold works well for this purpose. Dampen the soil before you work in the amendments to help the material to combine evenly. It is best not to overwork your soil. Gently mix the soil amendments into the top 2–4 inches of the soil and rake the surface smooth. Then water the plot wel to get the microorganisms working.
How to plant
Have a fertilizer on hand such as cottonseed meal that is in the range of 5-2-2. Gently break the cloves of garlic from the bulb. The largest cloves will grow the biggest bulbs. If you are planting different varieties, keep them separate and well-marked. Dig a trench about 3” deep, add the recommended amount of fertilizer and work it into the soil. Plant the garlic cloves 8” apart, giving them plenty of space for the bulb to form. Stand each clove up in the soil with the flat side down and the point up. Cover the garlic to about 1” above the tip of the garlic. Put in your plant stakes with the variety name at the end of each row. Water the bed to settle the soil and put a 3” layer of mulch over the bed. Less frequent, deep watering is the best practice for garlic to lessen the chance of bulb rot.
Fertilizing
Garlic is a heavy feeder. In the spring when there is 2–3” of new growth, pull back the mulch to warm the soil and apply the fertilizer you used at planting, repeating every 3–4 weeks until April. In May and June switch to a phosphorus fertilizer such as rock phosphate, bone meal, or bird guano to increase the bulb size.
In addition to the big 3 (N-P-K), garlic also needs these macronutrients: calcium, magnesium, and sulfur. There are also some micronutrients essential for garlic growth and development including iron, manganese, copper and zinc. Several applications of liquid kelp or kelp meal during the growing season can supply the additional nutritional needs.
Harvest time
In late spring, hardneck garlic will form scaping, a flower stalk which forms a whorl. Remove this stalk in the early growth stage. These are delicious when made into pesto or used in a quiche.
The first of June watch for the lower leaves of the garlic to begin to turn yellow. This is an indication that harvesting is close. For hardneck garlic look for 40-50% of the leaves to turn yellow. For softneck garlic look for 1/3 of the leaves to turn yellow. Dig up a few sample garlic bulbs and check to see if the bulbs have a uniform shape with good sized shoulders. If they are not ready, give them another week or two. When the bulbs have reached full size stop watering for a week to give the bulbs a chance to harden off a bit before harvest.
Using a garden fork (or a potato digging fork) gently lift the garlic bulbs out of the ground. Work the soil off the bulb and the roots, move the garlic to a well shaded area with good air circulation.
Curing
Lay the garlic out in a single layer. Make a second pass over the garlic, cutting the roots back by half and the stem to 9 inches in length. If air circulation is lacking, use an oscillating fan to keep the air moving for the first two weeks. Let the garlic cure for 3–4 weeks. At this time cut the roots to 1/4” and the stem to 1/2” and continue to cure for an additional 2–3 weeks. When there is NO green visible in the stem the garlic is ready for storage.
Storage
Garlic needs breathing room so wire-mesh baskets or mesh bags are the best containers. Low light, cool temperatures (35-55°) and moderate humidity (40-60%) is ideal for garlic storage. Garlic can be stored in the refrigerator but once it's removed from the cold it is very quick to sprout.
With some garden prep, meeting the nutritional needs of garlic, having patience for the long growing season, and careful curing, you can be richly rewarded with a bumper crop of garlic. You may well be the envy of your fellow gardeners, family, and friends.
IPM Garlic Pest and Disease Management
https://ipm.ucanr.edu/home-and-landscape/onions-and-garlic/index.html?src=307-pageViewHLS
Garlic Cultural Practices
https://ipm.ucanr.edu/home-and-landscape/onions-and-garlic/cultural-tips/index.html?src=307-pageViewHLS
Help Desk of the UC Master Gardeners of Contra Costa County (BHD)
- Author: Help Desk Team
Whether you fall into the camp of a little goes a long way or too much is never enough, I hope to convince you that growing garlic is worthy of your time and some space in the garden. Let's look at this amazing and ancient plant.
Historically garlic grew wild over much of Europe, Central Asia and the Far East. There are references to garlic going back as far as 5000 years ago. It is believed that softneck garlic was the first cultivated garlic. It has only been in the last 1000 years that the distinction was made between hardneck and softneck garlic.
Let's investigate the difference between hardneck and softneck garlic, as they vary in their structure, flavor, and growing requirements.
• Hardneck garlic is cold hardy and known for its robust, strong flavor. This garlic typically yields fewer cloves, with each clove being large and plump. Hardneck garlic has a central, hard stalk and produces garlic scapes, which are the flowering stem. These edible scapes are produced in late spring or early summer.
• Softneck garlic is better suited to growing in warmer climates. It has a milder, less pungent flavor profile. Softneck garlic bulbs have more cloves, but the cloves are smaller. Softneck garlic has no hard, central stalk and does not produce scapes, but if you want to braid your garlic, you need to grow softneck garlic. This is the grocery store type, available because it has a longer shelf life.
Planting garlic is easy but be aware when you put it in the ground you are dedicating that garden plot for 8–10 months. I like to use the rotation of putting garlic in the ground in mid-October which allows for harvest in June when the soil is warm enough to put peppers in the ground after the garlic is pulled out. Make sure you select a variety of garlic which is mature in under 240 days.
The reason for fall planting is that the lingering warmth of the soil allows the roots to get established and allows the bulbs to develop some leaf growth before colder weather begins. Garlic needs cold temperatures to stimulate root growth. Hardneck garlic requires 4–6 weeks of cold below 40–45° F. to develop a strong bulb. This chilling process is called vernalization. Softneck garlic is less demanding and does not need the extended chill hours. This makes softneck garlic a good choice where winter temperatures are mild.
Garlic will go dormant during the cooler months but will reawaken when the soil warms in the spring, giving it a jump start on the growing season. If you miss the October planting date, you can plant in February in our Contra Costa County growing zones, but your garlic bulbs will be small. Spring planting should be your last resort. In our clay soil, raised beds are a good choice, as garlic bulbs can rot in wet, clay soil.
It is recommended that you purchase “seed garlic” because it is grown for planting out and does not go into the grocery store pipeline. Seed garlic is bred to be pest and disease free. It will not have been treated with a sprouting inhibitor which may have been applied to grocery store garlic. I know gardeners who grow grocery store garlic successfully, but my personal choice is seed garlic, if for no other reason than the wonderful and diverse varieties available.
You will need to cover the garlic with a nice cushion of mulch during the colder months. Dry leaves or straw work well for this purpose. In the spring, when you see new growth on the garlic, pull back the mulch so the soil can begin to warm. When new growth appears, begin a schedule for fertilizing. Weeds are the enemy of garlic so weed early and often, but gently so you don't disturb the bulbs.
I hope you have the space and are willing to invest the time it takes to grow a bed of garlic. I think you will be richly rewarded.
For cultural information on watering, fertilizing, and harvesting, stay tuned for the next post.
Garlic: A Brief History (from the University of Missouri): https://ipm.missouri.edu/meg/2015/9/garlic-a-brief-history/
Help Desk of the UC Master Gardeners of Contra Costa County (BHD)