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In October, the time is ripe to plant ornamentals

Pumpkins, squashes and gourds
Around October, melons, pumpkins and winter squash will be ready to harvest when their stems have dried out and start to pull away a bit from the base.
(Getty Images)

It’s almost time: Soon we’ll wake up one morning and it will finally feel like fall — our best planting time.

Why fall? That’s when the air is cooler, yet the soil retains its warmth. Warm soil + cool air = ideal planting conditions for nearly every ornamental plant.

Here are the chores to take care of this month:

Edible gardens

Harvest melons, pumpkins and winter squash once their stems dry out and start to pull away from the base. Leave a few inches of stem attached as a handle. Rinse, dry and store in a cool, dry, dark location.

Let tomatoes, eggplants and squashes continue producing, or remove them to make room for cool-season crops.

Don’t compost old vegetable plants. Instead, send them off in the green waste so they can be hot-composted to kill pests and diseases.

Plant root vegetable seeds such as carrots, turnips and radishes directly into garden beds. Don’t buy them as seedlings; they don’t transplant well.

Start seeds for kale, cabbage, beans, cauliflower, spinach, lettuce and other leafy greens either in the garden or in containers to transplant in a month or so.

If winter gardening doesn’t excite you, give your garden a break. Rather than planting cool-season crops, plant cover crops to improve the soil. Legumes like hairy vetch add nitrogen; grains add organic matter. Buckwheat chokes out weeds, builds organic matter and suppresses nematodes. Choose the best cover crop seed for your garden. Order and plant the seeds now.

Swap out warm-season herbs like basil for cool-season herbs such as dill and parsley.

Plant lemony perennial herbs for seasoning and cooking: lemon grass, lemon verbena, lemon thyme and lemon balm.

Fruit trees and shrubs

Harvest pineapple guava. These egg-shaped, olive-green fruits grow on evergreen shrubs that reach 12 feet by 12 feet and make wonderful natural hedges. The plant’s botanical name is Acca sellowiana and it is native to South America but grows across Southern California. You know the fruits are ripe when they “self-harvest” by falling off the branches. Simply pick them up, slice lengthwise and scoop out the soft, sweet innards. Yum!

Pineapple guava (Acca sellowiana) grows across Southern California.
Pineapple guava (Acca sellowiana) grows across Southern California. The fruit is ripe when it drops from the branch.
(Getty Images)

Do you live in a citrus greening quarantine area? The Asian citrus psyllid spreads the bacteria that causes this fatal citrus tree disease, and it has been found across Southern California, prompting a state-enforced quarantine from Pasadena to Redondo Beach, south Irvine to Redlands and Camp Pendleton to Bonsall to Carlsbad. It is critically important not to move citrus fruits, leaves, wood or any other part of citrus plants anywhere inside or outside the quarantine area. Consume all fruits onsite. Don’t share fruits or plant parts. Don’t compost fallen leaves, branches or any prunings. Instead, seal them in a plastic bag and place them in a closed green waste can for collection.

Plant the last of the year’s subtropical fruiting trees and shrubs, such as banana, citrus, avocado, cherimoya or tropical guava. Unless you live within a few miles of the coast, plant now or wait until spring.

Order bare root deciduous fruit trees (nectarine, Pluot, apple, etc.) from your local nursery. They’ll arrive in the nurseries in January.

Are your citrus trees’ leaves curled and distorted? Do the leaves look marbled? That’s classic leaf miner. The larvae’s damage looks ugly but doesn’t hurt the tree or diminish production. Don’t cut off those leaves; removing infected leaves causes the tree to make new leaves, which also will become infected with leaf miner. Sprays won’t help. Just leave it alone.

Purple bottlebrush
Once daytime temperatures cool, you can start planting “unthirsty” plants native to California and other specific climates. From Australia, the purple bottlebrush adds striking color and volume.
(Getty Images)

Ornamental plants

In the shorter, cooler days of “second spring,” watch for established plants such as South African daisy (Arctotis) and Grevillea to erupt in bloom.

Once daytime temperatures cool, start planting trees, shrubs, vines and perennials. Focus on the “unthirsty” plants native to California, South Africa, Australia, the Mediterranean and western Chile.

  • Easy-to-grow California native plants include elderberry, agave, lemonade berry, oaks and different kinds of mallows.
  • Options from Australia include kangaroo paws (Anigozanthos), knife leaf acacia (Acacia cultriformis), Queensland bottle tree (Brachychiton rupestris) and purple bottlebrush (Callistemon Jeffers). All are incredibly drought-tolerant and easy to grow. Mulch but don’t fertilize. Phosphorus-containing fertilizers can kill these plants.
  • From South Africa, we can grow dozens of kinds of aloe, including torch aloe (Aloe arborescens). Succulent Bulbine frutescens has ever-present yellow flowers, while deep-green blades of grass like Cape rush (Chondropetalum elephantinum) dance in the breeze.
  • Among the Mediterranean region plants are blue-bladed spurges such as Euphorbia characias, myrtle (Myrtus communis), olive (Olea europaea), and Jerusalem sage (Phlomis fruticosa).

    Shorter and cooler days are perfect for planting ornamental plants like the Peruvian lily.
    (Getty Images)

  • From Chile, try purple-flowering Calandrinia, Chilean guava (Ugni molinae), Chilean wine palm (Jubaea chilensis), turquoise-flowered silver puya (Puya alpestris) and Peruvian lily (Alstroemeria).

Check your garden for emerging green spears of spring bulbs such as Sparaxis, Homeria and Gladiolus. If you have bulbs you’ve been meaning to plant, do it now. They may not flower next spring, but they’ll bloom the following spring.

Euphorbia characias, native to the Mediterranean region, also does well in San Diego's climate.
Euphorbia characias, native to the Mediterranean region, also does well in San Diego’s climate.
(Getty Images)

Plant annual spring flowers this month and next: California poppies, native farewell-to-spring (Clarkia), native tidytips (Layia platyglossa), flowering sweet peas and many more. Keep the seeds damp until they sprout. Keep young plants damp until rains begin.

Cut back spring and summer blooming sages (Salvia) so they can re-sprout fresh and flower again.

Divide iris, including native iris and Pacific Coast hybrids. Carefully separate the rhizomes (they look like tiny, jointed potatoes) at the “joints.” Use a sharp knife wiped clean with alcohol. Wipe the knife with alcohol again between plants so you don’t spread pests or diseases from one plant to the next.

Early in the month, shorten branches of scented geraniums and Martha Washington geraniums by a couple of inches. Next month, cut the long branches to force the plant to grow new shoots at the base.

Feed roses with liquid fertilizer at midmonth. Inspect leaves for mold, rust or black spot. Remove infected leaves and put them in the green waste bin rather than your compost pile.

Garden prep and maintenance

Rake up leaves as they fall from fruit trees. Unlike with ornamental plant leaves, send these leaves to the green waste, where they’ll be composted at a high temperature to kill bacteria, molds, etc.

Before you plant anything new, be sure your garden has a solid infrastructure:

  • Establish a solid irrigation system using inline drip irrigation (not individual emitters). Create “hydrozones” of plants that have the same water needs, then irrigate them accordingly.
  • Keep rainwater onsite and out of the gutter by directing it away from your house and into planting beds or bioswales.
  • Remedy heavy clay soil, hard-packed subsoil or fast-draining sand by layering on four or more inches of coarse, wood mulch or arborist chips (ground-up trees) that are 1 inch or smaller. Water well, then let it sit at least four or five months. Beneficial microbes and tiny critters break down the mulch, incorporating it into the soil. You’ll be amazed at how much richer the soil will be and how much better it will drain.
  • If your garden beds are flat, create height and contour using imported soil up to 18 inches high. Use a soil mix of 30 percent organic matter to 70 percent inorganic soil for all California natives and other waterwise, Mediterranean climate and desert plants.
  • Clean drains and rain gutters before the (hopefully) rainy season begins.
  • Do rain barrel maintenance. Use remaining water. Clean out mold or algae. Make sure rain barrel seals keep out mosquitoes looking for a place to deposit their eggs. Check the valve from the downspout in preparation for diverting (rather than collecting) the first of the year’s rainfall, which is called the “first flush.”

How to plant

  • Water the plant in its pot and let it drain. Gently pull the plant out of its pot. Dig a hole as deep as the rootball is tall, and slightly wider. Make the hole square instead of round, and rough up the edges. Add a few handfuls of worm castings to the hole, but no other amendments. Fill the hole with water and let it drain.
  • Carefully loosen the plant’s roots (except for bougainvillea or Matilija poppy, Romneya coulteri). Set the plant into the hole, just barely higher than the plant sat in the pot. Refill the hole with soil that came out of the hole. Wet the soil and tamp it down as you go along to eliminate air pockets.
  • When the hole is full, make a moat around the stem or trunk. Set your hose to trickle water into the basin and saturate the soil. Layer three or four inches of mulch onto the soil surface, starting at the outer edges of the basin. Cover the entire planting bed.
Use caution when replanting bougainvillea; the plants can die if their roots are disturbed.
(Getty Images)

  • Bougainvillea and Matilija poppy are extremely sensitive and die if their roots are disturbed at planting. To plant them, follow the directions above, but before you plant, gently cut out the bottom of the pot. Use your hand to support the bottom of the plant in its pot and gently move it into the prepared planting hole. Slice down the side of the pot on two opposite sides, then gently start to refill the hole with dampened soil. After a few inches, gently pull away the remaining portions of the pot, then finish refilling the hole and make the moat, etc.

Irrigation

With the sun lower in the sky, plants need less water, so adjust your irrigation clock to water just as long, but less frequently. If you have a “smart” irrigation controller, check to make sure it is making the necessary adjustments. If your controller isn’t smart, set it to run less often, but don’t alter the run time.

Smart irrigation controllers adjust your irrigation seasonally, zone by zone, depending on the type of plants each zone waters, your garden’s location, the type of soil, slope, sun, shade and so on.

When you plant natives and other Mediterranean climate plants, water them with inline drip irrigation. Inline drip has emitters embedded in the lines and delivers water directly to the soil, where it penetrates down to the roots. Natives do great with this kind of drip irrigation.

Don’t use the type of drip that has individual emitters at the base of each plant. These kinds of systems are neither durable nor reliable.

How long should you water? There is no one answer. Always water long enough to saturate the plant’s deep roots. Use your fingers or a soil probe to feel how deep the water has gone. Adjust your watering schedule so water reaches the deep roots every time. For drought-tolerant plants, let the soil dry several inches down before deep watering again.

Mulch

Renew your garden’s mulch using organic mulch (made from leaves, bark, wood, etc.) for non-succulent plants. Mulch succulents and cactuses with rock or decomposed granite. Whichever you use, keep the mulch 3 to 4 inches thick.

Organic mulches act like a sponge to hold water, keep moisture in the soil and protect soil from erosion. As the mulch breaks down, it feeds the micro flora and fauna that help build healthy soils to support plants. Research shows that mulch can protect plants from soil pathogens, too.

While mulch should cover the soil surfaces in your garden, leave several bare spots for native, ground-dwelling bees — very important garden pollinators that rarely sting.

Nan Sterman is a waterwise garden designer and writer and the host of “A Growing Passion” on KPBS television. For more information, visit agrowingpassion.com and waterwisegardener.com.