Happy New Year. May 2024 be a year of bountiful gardens, green thumbs and happy gardeners.

Prepare for rain

• The National Weather Service modeling predicts a “historically strong” El Niño this winter, the first in five years. What does that mean for gardens? A warm winter and usually, rain.
• Keep rain gutters clean. Decomposing leaves and other gunk “harvested” from rain gutters make perfectly good compost.
• Empty rain barrels between rainstorms. Use the water to irrigate your garden.
• Clear drains and culverts so water doesn’t back up and flood.
• Set your irrigation controller to “rain sensor” so it doesn’t turn on during or right rains.
• Add places for water to pool and percolate into your garden’s soil: a dry streambed, swale or simple depression filled with mulch.
• After rain, stay out of your garden beds for several days. Standing and walking on wet soil compacts that soil.
• Warm, wet soil translates to lots and lots of weeds. Use a hoe to scrape them away as soon as they sprout, and definitely before they go to seed.

Winter cleanup

• Fallen leaves from deciduous fruit trees: peaches, plums, apples, etc. can spread disease and insects, so put them into greenwaste, not in compost.
• Cut dead branches off shrubs and trees.
• Deadhead spent flowers from perennials, flowering trees and flowering shrubs. Cut each flower stem all the way down to its base. Compost cuttings and stems narrower than a pencil.
• DO NOT prune off cold and freeze-damaged leaves, stems or branches. Leave the damaged parts to protect the rest of the plant from upcoming freezes.
• Rake walkways. Wet, decomposing leaves get really slippery.
• Mulch under and around plants with coarse, woody mulch (NOT BARK) for nonsucculent ornamental plants, straw for vegetables, and rock for succulents.
• Turn and mix cold compost piles. Use the finished compost to mulch your garden.
• Empty and clean pots whose plants have died. Recharge the old potting soil with some worm castings and compost, then use it with new plants.
• Collect hand trowels, pruning shears, hose end nozzles and other tools scattered across your garden. Clean them, then organize them into drawers, hang them on hooks, etc. in a potting shed, garage or other space that is dry and protected from critters.
• Store bagged granular fertilizer in a container with a water- and critter-tight lid.

Irrigation management

• Even without rain, the cooler weather and fewer hours of sunlight mean that plants need far less-frequent irrigation as compared with warmer months.
• Adjust irrigation frequency by season, but always water for the same amount of time.
• Monitor soil moisture. Plenty of winter hydration helps plants prepare for dry summer conditions.

• Check your irrigation system for leaks, breaks, kinks, etc.

  – Run irrigation zones one by one
  – Flush each line, whether drip or spray.
  – Convert overhead spray to inline drip irrigation.

Plant new deciduous fruit trees, vines and shrubs

Shop local nurseries for bare root fruit trees, vines, roses and other deciduous shrubs that arrive this month. “Bare roots” are 1- to 2-year-old plants grown in the ground, then dug up and washed clean of soil. They look like scraggly sticks with a wad of roots at the base, but don’t worry, they grow into vigorous, producing plants.

Some bare roots — stone fruits, apples and pears — are grafted, which means they are two plants fused into one:

• The fruiting wood (also called the “scion”) is the top part of the tree. It grows leaves, flowers and fruits.
• The rootstock is the bottom part of the tree and grows roots.

The best grafted fruit trees for your garden combine the best scion with the best rootstock. You’ll find different options for each:

Choose the fruiting wood based on:

• The fruits you most like to eat.
• How many chill hours your garden gets.
• The time of summer you want the fruit to ripen — early, midseason, late.

Choose rootstock based on:

• Your garden’s soil (clay, sand or in between).
• Pathogens present in the soil — harmful bacteria, fungi, etc.
• The size of tree you prefer: full size, semi-dwarf or dwarf.
• Your garden’s chill hours.

What’s a chill hour? Chill is basically an accumulation of overnight hours between 32 and 45 degrees from late fall through early spring. Chill is critical for these fruit trees to set fruit in spring.

Different named varieties require different amounts of chill, so it’s important to choose fruit trees that produce with the amount of chill your garden gets. Here’s a good reference: https://bit.ly/3Nzfaeo

Chill hours vary from your garden to your neighbors’, but in general:

• Inland gardens tend to get 100 to 500 chill hours.
• Gardens just inland from both the coast and desert gardens get 100 to 400 chill hours.
• Right along the coast, gardens get 100 to 300 chill hours.
• Mountain gardens, like Julian, can get up to 1,000 chill hours.

See how bare root plants are bred, grafted, grown, harvested, processed and shipped in the episode of “A Growing Passion” titled “From Fruits to Nuts.”

Bare root roses are similar to bare root fruit trees. Many are grafted to combine the ideal flower onto a strong rootstock. Don’t worry about chill hours. Instead, look for the blooms you like best on a strong root structure.

Prepare the site:

• Choose a spot in full sun (six hours-plus per day) during the growing season. Winter shade when the plant is dormant is not a problem.

• Do a drainage test. Dig a hole 2 feet wide by 2 feet deep. Fill with water and let it drain. Fill again and track how long the hole takes to drain out. If water is gone in a few hours, that’s fast-draining soil. If water sits for a day or two (or longer), that’s slow draining soil, aka “heavy” soil. The rest is in between. The rootstock should match the drainage.
• Bring inline drip irrigation to the area so you can complete the irrigation once you finish planting.

Shop for bare roots:

• Choose plants with pliable roots that are not too tangled. Roots should fan out wide rather than grow in a circle.
• For fruit trees, opt for low branches so fruits will be easy to reach.

The nursery will wrap the plant roots in plastic so the roots don’t dry out. Plant the same day you bring the plants home.

• If you can’t plant right away, put each plant into a pot more than big enough to accommodate the roots without folding them, then fill with damp construction sand or wood shavings. Be sure to plant them within a week or two.
• Remove the plant from the plastic and spread out the roots. Notice where the color changes on the trunk — that’s the “dirt line” from when the tree was planted in the ground. Mark the dirt line with a Sharpie so you don’t lose track.
• With grafted plants, there’s a thickening on the trunk above the dirt line. That’s the graft, the point where rootstock and the fruiting wood are grafted together. The graft always stays well above the soil.
• Cut the main trunk of any trees to hip height. As hard as it may be, it’s the best way to encourage low branches for easy care and easy harvest. It also balances the size of the plant to the size of the rootball. Shorten side branches to one or two buds long.
• Submerge the bare root in a bucket or trash can of water to cover the roots while you finish prepping the planting hole. The container should be big enough to accommodate the roots without bending or kinking them. Don’t leave the roots submerged for more than two hours.
• Dig a planting hole wide enough for roots to fit without bending, folding or crunching, and deep enough that once the plant is in the ground, the soil line on the trunk or stem matches the level of the soil after planting.
• Once the planting hole is the correct width and depth, toss in a few handfuls of worm castings, Fill the empty hole with water and let it drain out.
• As you plant, refill the hole with native soil only — no potting mix, no compost, no fertilizer — just native soil. Water to settle the soil around the roots as you go.
• Make a watering moat a foot or two away from the trunk. Add two loops of in-line drip, the first 8 or 10 inches away from the trunk, and the second a foot out from the first loop. You’ll add more loops as the tree grows.

Prune and spray established deciduous fruit trees and roses

• Prune roses to remove dead and diseased branches and to stimulate flowering in spring. Cut remaining branches back by a third and remove lingering leaves.
• Prune deciduous fruit trees to stimulate fruit production. Different kinds of fruits (peaches, plums, apples, etc.) fruit on different parts of the branches, so each is pruned differently. If you prune them incorrectly, you risk cutting off the fruiting wood.
• Learn how to prune from knowledgeable groups like the California Rare Fruit Growers, and the local Rose Society. Be cautious about videos you find online. Some of those people are really knowledgeable while some are not.
• Local nurseries and other experts offer pruning workshops. There are also very good pruning books, including my favorite, “How to Prune Fruit Trees and Roses” by Ken Andersen and R. Sanford Martin.
• Spray dormant fruit trees and roses now to prevent leaf curl, fire blight, downy mildew, aphids, scale and other problems in spring and summer. Use Liqui-CopTM or Daconil along with mineral-based horticultural oil. Each product should be sprayed three times before the trees start to flower in spring. Follow all label directions.

Citrus

• Harvest kumquats, Washington navel, Oro Blanco grapefruits, pummelos, Eureka lemons, limes and more as they ripen.
• Color does NOT indicate ripeness when it comes to citrus. If oranges are orange but taste bitter or sour, they’re not ripe. Taste is the best test for ripeness.

Vegetable garden

• In the nursery, buy onion sets (tiny onion plants), seed potatoes, bare root strawberries and more.
• Harvest root vegetables as you need them.
• With leafy greens, pick only as many leaves as you need at the moment.
• Feed brassicas — broccoli, kale, cabbage, etc. with all-purpose vegetable fertilizer.
• Watch for aphids. Shoot them with a hard spray of water using a Bug Blaster hose end nozzle.
• Holes and ragged edges in brassica leaves are usually from snails, slugs or tiny green worms. It may look ugly, but treat only when the damage is so extreme that the plant looks to be dying. If you treat, use Bt organic pesticide, which is specifically for worms and mosquito larvae. Bt kills caterpillars too, so keep it away from passion vines, parsley, dill, fennel, milkweed and other plants that attract butterflies.
• Let some parsley, dill and cilantro reseed for an ongoing supply.
• Continue to plant from seed: rutabaga, carrots, beets, turnips, radishes, leafy greens.

Plant ornamental plants

All native and nonnative drought-tolerant plants are best planted in the cool months.

• Start small. A 5- or 15-gallon plant grows faster and stronger than one in a larger container. A 1- or 5-gallon shrub grows faster than a larger one.
• Check the roots. Reject plants with exposed roots, tangled roots, roots that circle the trunk or sit above the potting soil, etc.
• Plant properly. Set the plant at the same level it was in the container. Loosen up the rootball. Do not amend the planting hole.
• Water consistently if it doesn’t rain. New trees, shrubs etc., need to be kept damp (not wet) through their first year or two in the ground. Then, cut back on water.
• Leave leaves. Despite what your parents said, leaves in garden beds are good. Leaves from ornamental plants (not fruit trees) become mulch. Rake pathways and patios. Everywhere else, leave the leaves.
• Cover all garden beds in a 3-inch layer of mulch. Leave a 10-by-10-foot area bare for native ground-nesting bees (they won’t sting you).
• Plant pooped-out poinsettia in your garden. Choose a spot where the night sky is totally dark from September to December. The long dark period stimulates next winter’s bloom. Poinsettias like good drainage and little water. Fertilize monthly once daytime temperatures are above 60 degrees (download my How-to Care for Poinsettias at bit.ly/careforpoinsettia).
• Keep potted plants damp but not too wet.

Houseplants

• Heating houses dries out the air, and that’s on many houseplants. So, give your plants a spa day — in the bathroom! Fill the tub with a few inches of water. Prop your houseplants on top of empty plant pots (upside down) or other “props” set in the tub. Allow the houseplants to enjoy the humidity but not sit in water. Leave them for a day or so.
• Check houseplants for aphids, mealy bugs or scale. Use a cotton swab dipped in alcohol to kill the critters.
• An inch layer of fine gravel or rounded pebbles over the top of potting soil stops fungus gnats from laying eggs in damp potting soil, and soon, they disappear.

Sterman is a garden designer, journalist and the host of “A Growing Passion” on public television. She runs Nan Sterman’s Garden School at waterwisegardener.com.