Marin Master Gardeners
University of California
Marin Master Gardeners

Propagation

Looking for lots of new plants? Look no farther than your home garden (and your friends and neighbors) to expand your plant collection. Fall is the ideal time to plant seeds as well as propagate by plant division, stem, or root cuttings.

Daylilies
Plant Division: refresh your perennials, get more plants
Daylilies blooming less profusely? How about your dahlias? Agapanthus looking crowded and less vigorous? If so, it might be time for a bit of digging, dividing, and sharing. Propagating -- aka multiplication by natural reproduction -- of many perennials and bulbs is not only easy and economical, but it's also beneficial for your plants.

Many of our well-loved perennials and bulbs reproduce, sometimes exponentially. Each season, well-cared-for plants send out new growth just waiting to be welcomed to a new home.
Plant division is an excellent way to increase your plant supply. Not only will dividing provide additional plants for your garden, but it will also encourage robust blooming to overcrowded perennials. Our traditional rainy season is an ideal time to divide spring and summer bloomers. Do your garden a service by dividing established beds, spreading your bounty around the garden, and sharing with friends.

How do you know when your perennials need to be divided? Sometimes a clump will spread and leave a doughnut-type hole in the center as old plants die, or you may notice lots of foliage but not much flowering. Other symptoms to look for include stunted growth and/or yellowish leaves.

Here’s how to divide perennials:

1. Select and prepare the plant to be divided by giving it a moderate pruning.

2. Use a trowel or shovel to dig around the plant to be divided, leaving as large a soil ball as possible.

3. Lift the clump gently from the ground.

4. Divide the main clump into several smaller clumps along the obvious separation points. Often you can gently tease the roots apart and separate the clump into smaller sections. However, if the clump is seriously overgrown and the roots are badly tangled, pry the roots apart using two spading forks. Insert one fork into the center of the clump, then insert a second fork back to back with the first. Push the two handles toward each other, and the roots should separate. Be sure to use clean, sharp tools. Sanitize your equipment with a solution of one part bleach to nine parts water to prevent the spread of any disease.

5. Discard the older, less vigorous portions of the clump and save the newer, healthier divisions for replanting. Healthy roots should have a white, sturdy appearance.

6. Replant the newly divided plants directly into the garden. Prepare the area to be replanted by amending the soil with compost or other organic material to ensure that new plants become established quickly. Plants may also be potted up into containers for sharing with others.

7. Water plants thoroughly after planting.

8. Follow up a week later with a light liquid fertilizer application.

9. Provide protection from too much sun, wind, and extreme temperatures.

Dahlias will produce more flowers if they’re divided.
Dahlias will produce more flowers if they’re divided.
Perennials that benefit from dividing include coreopsis, chrysanthemum, daylily, delphinium, iris, lamb’s ear, penstemon, scabiosa, Shasta daisy, and yarrow. Dividing these plants reduces their size and stimulates fresh new growth. And, of course, it’s an inexpensive way to create additional plants for your garden or to share with friends and neighbors.

In many parts of the country, dahlias must be dug up each fall and protected from freezing weather. This annual digging allows for careful dividing and editing. Here in Marin County's moderate climate, it's easy to just let our dahlias stay in the ground year round. However, it's important to learn about dividing your dahlias so that you can enjoy more flowers. One important tip: when dividing dahlia tubers, be careful to keep at least one "eye" on each fat tuber. Look for the white or pinkish dots on the tuber, which is where the new stem will originate.


Seeds: collect, store, sow

Seed collecting is easy, economical, and can become addictive. By saving seeds, you can develop plants in your garden while participating in an ancient tradition that preserves genetic and cultural diversity. Follow these steps to collect and sow seed.

Collect
1. Look for dry seed heads where your favorite flowers have bloomed. Reliable plants for beginners include foxglove, marigold, cosmos, Shasta daisy, and sunflower. Allow the seed to mature and dry as long as possible on the plant. When the flowers and pods are faded and dry, it's time to harvest.

2. Clip or shake them directly from the plant into a paper bag OR spread your collection in a single layer on a screen for up to a week to complete the drying process. Seeds harvested from a dry plant should be threshed to separate the seed from their cases. You can gently crush your harvest between two pieces of cardboard to separate the seeds, then toss them in the air or pour them from one container to another near a fan to winnow away the chaff. The light casings will blow away leaving you with the seed. You can also use a sieve to separate the two.

3. The seeds of fleshy fruits, such as cucumber, tomato, squash, and melon, should be scooped out, washed, and dried. Some gardeners ferment these seeds, especially those of tomatoes, before drying. It's not essential, but it helps sort out the bad seeds and helps kill diseases. If you decide to ferment, add the seeds to a little water in a jar and place in the sun. After a few days, carefully remove any moldy film, add more water, and stir. The good seeds will sink to the bottom. Pour off any floating pulp and seeds, then repeat the process until all the pulp is gone. You can now drain and dry the seeds in a single layer on a screen or a paper plate.

*Important: be sure you know which kinds of seeds you can save. It’s easiest to begin with standard or heirloom varieties that are self-pollinating. (Hybrid plants are created by crossing two unrelated parents. Their seeds are sometimes sterile and do not breed true.) Some common self-pollinators are tomato, lettuce, pea, snap bean, soybean, lima bean, endive, and escarole. Look through your garden and select the healthiest plants with the qualities that you would like to encourage -- the tastiest tomatoes, for example, or the earliest or the largest. Tag your selected plants with a stake or cord to make sure you don't mistakenly eat your prize seeds in a dinner salad.

Store
4. Store your dried seeds in an airtight container in a cool place to avoid exposure to moisture and heat. Mark the container with the name of the plant, the date, and any notes on color, location, or size.

Seedlings appreciate light and warmth to germinate. Photo: Nina Cunnan
Seedlings appreciate light and warmth to germinate. Photo: Nina Cunnan
Sow
5. If you're starting seeds indoors, use sterile soil, readily available at your local garden center.

6. If you're planting outdoors, just be sure the soil is loose and uniform in texture. Be sure to only cover seeds to about the depth of the width of the seed. This means that tiny seeds barely get any cover. In fact, some seeds prefer to be left uncovered. Why? Because seeds need light and warmth to germinate. That's why they also need plenty of sun (outdoors or near a window) for germination.

7. Watering can be tricky. Seeds are like the baby bear: they don't want too much or too little water. They want it just right. Aim to keep the soil moist but not saturated. And avoid planting seeds outdoors in cold, damp weather, since this could be a recipe for failure.

8. Some seeds are quick to germinate while others require considerable time -- be patient and keep the soil moist and warm while you wait.

Succulents are among the easiest plants to propagate. Photo: Gail Mason
Succulents are among the easiest plants to propagate. Photo: Gail Mason
Succulents: finding new homes for all those pups
Succulents -- those colorful, fleshy, unthirsty plants -- are about the easiest plants of all to propagate. With succulents, you can often see the baby plant growing right on the mama plant. All you do is snap off these "pups" and pop them into well-draining soil and you're done. You may have greater success if you wait a day or two for the stem end to form a callous before planting. It’s that simple!

Cuttings: snip and plant
Propagation through cuttings isthe process of using a piece of an existing plant and encouraging it to regenerate itself into a new plant. Stems, leaves, and roots can all be used for cuttings. This is a good method for woody and herbaceous plants. Always take your cuttings from healthy and vigorous plants. Here’s how to propagate by cuttings:

1. Using a clean, sharp knife or razor blade, cut a 3 to 6-inch branch from a semi-hardwood plant such as camellia. Ensure cleanliness by dipping your cutting tool in a solution of nine parts water to one part bleach. Ideally, collect your cuttings in the morning when plants are most hydrated. Immediately wrap the cuttings in moist towels. A good cutting will be just below a node, have some intact buds or leaves, and three to five nodes.

2. Remove the leaves from the bottom half. 

3. Use a rooting hormone on the stem prior to placing it into the planting medium.

4. Place your cutting in a pot filled with a potting medium. Perlite and vermiculite make good medium. The goal is a light, airy mixture that allows water to flow through while retaining moisture. Experiment to see what works best for you. Most importantly, the medium must be kept moist, with moderate light, in a protective environment, which can be as simple as a plastic bag supported by chopsticks or as elaborate as a moisture and temperature-controlled greenhouse.

5. Tag your cuttings! It’s easy to think you’ll remember what that little cutting is and when it was started -- but wouldn’t it be easier to get in the habit of adding a marker to each start, identifying the date and the plant cloned?

6. Rooting should occur within four to six weeks. Keep your cuttings moist.

Stem cuttings are probably the easiest and most common method. To propagate from spring growth of deciduous or evergreen plants, use the softwood stem tip cutting method. Detach a two to six-inch piece of stem, including the terminal bud. Make your cut just below a node. Remove flowers and flower buds so that all the plant's energy will go to root formation. Also, remove all lower leaves that might touch the rooting medium. Dip your cutting into a rooting hormone and then place it into rooting medium such as a mixture of sand, vermiculite, soil and water, or a mixture of peat, vermiculite, and perlite. Keep your cuttings moist and you should have roots in two to five weeks.

Hardwood plant propagation with deciduous plants occurs during their dormant season (after the plants have lost their leaves). Collect your cutting(s) from the wood of last season's growth. Cuttings should be approximately between six and 20 inches long. The diameter of the cutting should be between one and two inches. Use a rooting hormone on the end of each cutting, then bundle them together and place in a plastic bag, moist sawdust, or peat. Keep the cuttings in a dark cool area. The cutting can be planted outside as soon as rooting occurs.

Leaf cuttings are most commonly used for indoor plants including African violets and Rex begonias. For African violets use the entire leaf, leaf blade, or a portion of the leaf blade. Place the leaf cutting vertically in a rooting medium (perlite works well) after applying a rooting hormone. The new plant will form at the base of the leaf or at the midrib of a leaf blade. For plants with split leaves (e.g., Rex begonia), start with a mature leaf from your chosen plant. Cut its large veins in the lower leaf surface and place it lower side down on the rooting medium. The new plant should grow where the cut was made. Both types of leaf cuttings should be kept under moist conditions, and the new plant planted when it appears strong and vital.

Time of year can be important. Fall and early winter are ideal for propagating many California natives as they show healthy new growth when the rains fall. Cuttings from some plant species will root almost anytime.

Try your hand at one or all of these propagation techniques and share your bounty with friends!


Original text by Marie Narlock and Jane Scurich for the Marin IJ, plus Suzzanna Walsh and Marilyn Geary
Edited for the Leaflet by Jane Scurich

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