Dividing Perennial Plants

As the blooms fade on your perennial plants, the opportunity arrives to propagate your favored specimens by through root division.

The best candidates for this process will have been growing for at least two years, and preferably a bit longer. The ideal time for propagation by root division is after a healthy plant has had time to develop a substantial root system, and before it has become crowded and less productive of blossoms. When divisions are planted, they should be watered lightly and shaded temporarily to limit loss of moisture.

The preferred time of the year to divide perennials is early spring or early fall, rather than the mid-spring to late summer period, when perennial plants are growing and producing blossoms. With this schedule in mind, right now is a good time to consider which plants to divide. This timing gives the divided plants the fall and winter months to develop roots and prepare to burst into bloom next spring.

The general guidelines mentioned above apply to all kinds of perennial plants, but the process differs somewhat with broad categories of these plants.

Rhizomatous and Tuberous Plants

Plants that grow from rhizomes or tubers can be dug up carefully with a garden fork, separating the rhizomes or tubers by hand or knife, and replanted at the same depth as the original plant. Tuberous plants include Arum, Calla (Zantedeschia), Canna, Dahlia, Spurge, and others.

Examples of rhizomatous plants are Iris, Canna and Bergenia. Other in this category: ginger (Zingiber officinale), the related White Ginger Lily (Hedychium coronarium), and the bamboos, which are members of the grass family (Poaceae) and manage propagation quite well on their own.

Blossom of White Ginger Lily
Rhizome of White Ginger Lily

Once dug and divided, these plants could be replanted immediately, or should be kept in a cool and dark place until a convenient time for replanting in the fall.

Clumpers

Another category of perennial plants is the “clumpers,” which have fibrous root systems and clumping growth habits. These plants’ root balls can be dug up with a garden fork or spade, and then either pried apart by hand or split with the spade. The gardener might need to use two garden forks to divide really large root balls.

The number of divisions to be made from a given plant will depend upon the size of the root ball. Often, dividing the root ball into four quarters will be appropriate. While a larger number of smaller divisions might be desirable, they could require more time to become ready to bloom.

The roots of divided plants in this category should not be allowed to dry out. Ideally, they should be dug during an overcast day, replanted promptly, and watered in. Trimming the foliage to reduce transpiration also will help the plant to bounce back from the process.

The clumpers comprise a large group of perennial plants. Examples: coral bells (Heuchera), cranesbills (Geranmium), columbines (Aquilegia), daylilies (Hemerocallis), plantain lily (Hosta), primroses (Primulus), lamb’s ears (Stachys), bugleweeds (Ajuga), Japanese anemone (Anemone hupehensis, which propagates readily on its own), stonecrop (Sedum), yarrow (Achillea), and several larger grasses.

Runners

These plants have shallow stolons or thin rhizomes, and spread across the ground. They can be divided in the same as way as clumpers. Examples include bee balm (Monarda), goldenrod (Solidgo), and aster (Symphyotrichum).

Plants with Woody Crowns

Plants that have woody crowns can be divided with somewhat more effort than other categories. The basic process is the same as for fibrous-rooted clumpers but typically require cutting the root structure apart with garden shears or saw, e.g., a pruning saw.

Examples of these plants include Astilbes, bear’s breeches (Acanthus), foxtail lilies (Eremurus), goatsbeard (Aruncus), lilyturf (Liriope), peonies (Paeonia), and wild indogo (Baptisia).

Plants Best Not Divided

Some plants have root structures that do not divide well: they might have single taproots or single woody roots, and are best propagated by seed. These plants can be recognized easily when they have been dug up. Examples include lavender (Lavendula), Russian sage (Perovskia), Allysum, carnations (Dianthus), Euphorbias, foxgloves (Digitalis), butterfly weed (Asclepias), and others.

Dividing perennials can be a satisfying project for avid gardeners, and the most inexpensive way to multiply favored plants to the landscape. Tour your garden in a search for division candidates. 

Propagating Softwood Cuttings

I like to know the names of the plants in my garden, partly because I can Google them for information about cultivation and routine care. I also want to know their geographic origin because I have organized my garden in Mediterranean climate zones, and want the plants to be in the right zone.

That’s a bit wonky, I know, but that’s how my garden is organized.

Despite that need for plant names, I lost track of the name of a plant in the Australian area of my garden. Here is the plant:

Teucrium betonicum - close up

Teucrium betonicum

By chance, I came upon the plant’s name while searching the Internet for examples of landscape designs for Mediterranean climate gardens. It is a Madeira Germander (Teucrium betonicum), which is from the Madeira Islands, which are in the Atlantic Ocean, near the Canary Islands. That area is within my informal definition of the Mediterranean climate zone.

Other germanders are native to other parts of the Mediterranean area. A popular plant for Mediterranean climate landscapes is the Bush Germander (Teucrium fruticans). My germander is considered “relatively rare,” which I find appealing for some reason.

This plant grows vigorously, rising to just over six feet with evergreen foliage and showy spikes of rose-violet flowers. According to my landscaping plan, however, it is in the wrong place. This plant grows vigorously, rising to just over six feet with evergreen foliage and showy spikes of rose-violet flowers. According to my landscaping plan, however, it is in the wrong place.

I’d like to move the plant to the Mediterranean area of my garden. I might give that a try during the winter months after it is out of bloom and into dormancy. It might move easily and survive nicely, or the process might kill it.

I might look for a replacement plant, but I haven’t seen this “relatively rare” plant in local garden centers and searches of mail order sources were unsuccessful.

An alternative approach is to propagate the plant from tip cuttings. This strategy requires time for the new plants to grow to maturity, but it is easy and inexpensive. I could use three specimens in my Mediterranean garden, and growing three new plants would require only slightly more effort than growing one.

As it happens, late spring/early summer the right time of the year to propagate shrubs. The most difficult part of the process is to take cuttings at the right maturity, called softwood. Greenwood cuttings are too young, and woody cuttings are too mature. Softwood snaps when bent, while green wood bends without snapping and wood does not bend.

Take a softwood cutting that has two or three leaves, and neither bud nor blossom. Cut an inch or so below the bottom leaf, then remove the bottom leaf. This leaves the leaf node from which roots will develop. Treat the leaf node with root hormone (available at garden centers), and insert the cutting into moist potting soil. Press the soil around the cutting to eliminate air pockets, and place the cutting in a warm spot with indirect light. Keep it moist (not wet) for about a month, and test for root growth by tugging gently on the cutting. Once roots have formed, maintain the plant as it grows to begin enough for transplanting in the garden.

This outline of softwood propagation shows that the process is not difficult; more detailed descriptions of the process are available in books or on the Internet.

If you haven’t tried propagating a favored shrub from your garden or another’s garden, right now is a good opportunity to try this “real” gardening activity. Propagation is most satisfying when you could use several clones of a plant to develop your garden or to give to friends.

Propagating Plants

According to meteorologists, the Spring Equinox occurs tomorrow (Saturday), just before midnight, but the first full day of spring will be on the following day (Sunday).

In any event, spring’s arrival inspires many thoughts of gardening opportunities. This column addresses three timely tasks.

Propagating Plants from Cuttings

First, real gardening includes the propagation of plants. One method for getting new plants that is particularly good in the early spring is taking cuttings from existing plants. The timing is good because cutting from the new growth of existing plants can be rooted easily.

Practicing this technique is both frugal and fun, so survey your garden and the gardens of others for plants that you would like to propagate, either to add to your own garden or to gift to other gardeners. If you want more of someone else’s plants, ask permission to take cuttings!

Start by preparing your containers, e.g., small plastic nursery pots, by filling them with planting mix from a garden center, rather than garden soil, which might have bacteria or fungi that could harm young plants.

Using clean clippers, take cuttings of about three inches from the tender green growing tips of plants. The cuttings should be flexible, not woody.

Strip the lower leaves from the cuttings, and insert the stems into damp soil. Place the planted containers where they will be warm but protected from direct sunlight.

Follow up by keeping the cuttings moist. This involves occasional watering and perhaps providing a mini-greenhouse of plastic sheeting to reduce water loss from evaporation. If moisture condenses on this covering, the cuttings could be too moist and vulnerable to fungal problems, so remove the covering for an hour or two to let the excess moisture evaporate.

Your new plants could require several weeks to establish roots, at which time they will develop new leaves. To check their status, tug very gently on the cutting to detect resistance from the new roots.

When you have rooted cuttings, move the plants into larger containers or the garden, and congratulate yourself.

Propagating Plants from Seeds

Planting seeds is also a frugal and fun approach to real gardening. The process is very similar to propagation from cuttings, but it offers a broader range of options and requires more time.

Seeds are available from garden centers. If you want to grow varieties that are not offered by a local garden center, visit Cyndi’s Catalog of Garden Catalogs (www.gardenlist.com/) for many, many options.

Almost all seed packets have basic instructions for growing the particular seeds.

Propagating Plants from Plant Sales

You could get more of the plant you like by just buying them. That approach also works for plants that are new to your garden!

Mark April 9th on your calendar for the combined plant sales of the UC Santa Cruz Arboretum and the California Native Plant Society, Santa Cruz County Chapter. For information, visit the Arboretum’s website (arboretum.ucsc.edu/news-events/events/).

Mark April 23rd & 24th on your calendar for the Spring Show & Sale of the Monterey Bay Area Cactus & Succulent Society. For information, visit the Society’s website (mbsucculent.org).

Spring is here and time to enjoy your garden!

Pruning Daphnes and Salvias

According to meteorologists, the Spring Equinox occurs tomorrow (Saturday), just before midnight, but the first full day of spring will be on the following day (Sunday).

In any event, spring’s arrival inspires many thoughts of gardening opportunities. This column addresses three timely tasks.

Propagating Plants from Cuttings

First, real gardening includes the propagation of plants. One method for getting new plants that is particularly good in the early spring is taking cuttings from existing plants. The timing is good because cutting from the new growth of existing plants can be rooted easily.

Practicing this technique is both frugal and fun, so survey your garden and the gardens of others for plants that you would like to propagate, either to add to your own garden or to gift to other gardeners. If you want more of someone else’s plants, ask permission to take cuttings!

Start by preparing your containers, e.g., small plastic nursery pots, by filling them with planting mix from a garden center, rather than garden soil, which might have bacteria or fungi that could harm young plants.

Using clean clippers, take cuttings of about three inches from the tender green growing tips of plants. The cuttings should be flexible, not woody.

Strip the lower leaves from the cuttings, and insert the stems into damp soil. Place the planted containers where they will be warm but protected from direct sunlight.

Follow up by keeping the cuttings moist. This involves occasional watering and perhaps providing a mini-greenhouse of plastic sheeting to reduce water loss from evaporation. If moisture condenses on this covering, the cuttings could be too moist and vulnerable to fungal problems, so remove the covering for an hour or two to let the excess moisture evaporate.

Your new plants could require several weeks to establish roots, at which time they will develop new leaves. To check their status, tug very gently on the cutting to detect resistance from the new roots.

When you have rooted cuttings, move the plants into larger containers or the garden, and congratulate yourself.

Propagating Plants from Seeds

Planting seeds is also a frugal and fun approach to real gardening. The process is very similar to propagation from cuttings, but it offers a broader range of options and requires more time.

Seeds are available from garden centers. If you want to grow varieties that are not offered by a local garden center, visit Cyndi’s Catalog of Garden Catalogs (www.gardenlist.com/) for many, many options.

Almost all seed packets have basic instructions for growing the particular seeds.

Propagating Plants from Plant Sales

You could get more of the plant you like by just buying them. That approach also works for plants that are new to your garden!

Mark April 9th on your calendar for the combined plant sales of the UC Santa Cruz Arboretum and the California Native Plant Society, Santa Cruz County Chapter. For information, visit the Arboretum’s website (arboretum.ucsc.edu/news-events/events/).

Mark April 23rd & 24th on your calendar for the Spring Show & Sale of the Monterey Bay Area Cactus & Succulent Society. For information, visit the Society’s website (mbsucculent.org).

Spring is here and time to enjoy your garden!

Irrigation for a Small Greenhouse

Another rainy day project in the garden!

Several years ago, with the help of a friend, I installed a greenhouse in a corner of my garden. This is a typical backyard structure, just ten-by-twelve feet, not an expansive “plant factory” like those on the annual open greenhouse event hosted by local nurseries for mostly flowers.

Greenhouse-large

My greenhouse, although small, has ample bench and shelf space for an ambitious program of propagating and maintaining plants. Plants will assume the primary role of growing, and a greenhouse can easily exclude deer and gophers, but operating a greenhouse still requires investments of the gardener’s time for planning, planting, monitoring and controlling climate, diseases and the smaller pests.

Best intentions aside, other priorities can leave the greenhouse unattended. When that has happened to me, my plants have tended to expire.

In addition, my greenhouse developed another problem. I had installed a sprinkling and misting system to irrigate the plants, using an inexpensive battery-operated timer. It worked fine until the battery died when the irrigation valves were open. The timer did not have the power to close the valves, so they ran for days, unobserved. This resulted in soggy plants, a huge water bill and attendance in a water conservation workshop.

I turned off the system in favor of watering by hand, but because the greenhouse is away from the house, it was easy for me to neglect the watering schedule. Except for some succulents, my plants did not do well under that plan. A clear need existed for a reliable automatic irrigation system.

Working with another gardening friend, we are installing such a system, with the longer-term objective of starting seeds, growing new plants to garden-ready size, and maintaining surplus plants for giving to other gardeners. (I could also grow plants for sale, but the small-scale nursery business would seem uneconomic.)

The irrigation system includes a professional grade controller, capable of scheduling four irrigation valves, and two valves plus capped connections for two future valves. Wires running the length of the greenhouse support flexible tubing over plants, which will be on tables or shelves (not on the ground). The tubing will have multiple emitters that will either spray or drip water on the plants. Spray is best for groups of seedlings or small plants while drip is more effective for larger plants.

Some gardening friends use their greenhouses to maintain collections of succulent plants that require warm, dry conditions, or orchids or other tropicals that require warm and moist conditions. Greenhouses in public gardens often focus on one or the other of these plant groups.

When planning a greenhouse for the home garden, a good first step would be to decide which plants are to be grown, and what climate those plants will need: cool/moderate/warm, or dry/tropical. To learn about these options, search the Internet for “types of greenhouses.”

My greenhouse is intended to moderate temperatures, year-round, and to control moisture levels through scheduled spray and drip irrigation. This growing environment will support a wide range of plants, excluding only those that require extreme conditions. Plants that require a winter chill, for example, grow poorly in the coastal Monterey Bay area, whether in a greenhouse or in the ground.

The home gardener can use a greenhouse to extend the growing season, protect against larger pests, and control the environment for either specialty plants or general gardening. Greenhouse management can be an engaging and satisfying form of gardening; it can also be more expensive and time-consuming than conventional gardening. Enter with eyes wide open.

 

Propagating Plants

Plant and cutting exchanges, which are popular in the Monterey Bay area, invite gardeners to bring plants or cuttings from their garden to swap for plants or cuttings offered by another gardener. These exchanges work because plants propagate naturally on their own: the gardener does not incur a significant cost, and still reaps the satisfaction of giving something of value to another gardener.

Cheap thrills!

Propagating plants for sharing require a significant investment of time: growing plants from seeds or cuttings and then giving them away could amount to a generous gift of the gardener’s time. However, opportunities exist for sharing plants with little effort.

For example, if your daffodils or irises need dividing, you could very well end up with a surplus of bulbs or rhizomes that you could share.

Another example: plants might self-propagate in your garden to the point that you have more than you want, and would prefer to reclaim the space for other plants.

Plants have many ways to reproduce, and gardeners can support those natural processes successfully, and with both botanical creativity and economic efficiency in developing the garden and sharing with friends.

For an introduction to this topic, visit Wikipedia website <en.wikipedia.org/wiki> and search for“Plant propagation.” This site provides very brief descriptions of sexual propagation, which involves growing plants from seeds, and asexual propagation, which encompasses several methods:

11-21-14 Cotoneaster berries CU

Cotoneaster lacteus

Cotoneasters produce seeds copiously, perhaps as an adaptation to the many birds that find them tasty. This specimen is C. lacteus, called Pareny’s Cotoneaster or Red Clusterberry. The name for the genus, native to China, is derived from ‘cotone’, an old Latin name for the quince plant, plus ‘aster,’ which means “resembling” indicating that this plant looks like a quince.

 

10-21-14 Anemone blossoms - fading

Anemone hupehensis var. japonica,

Japanese Anemone blossoms are fading about now. These plants are best propagated from root cuttings taken in the late fall or early winter. When we lifted them, we saw vigorous new white shoots on the roots, and knew that they would re-root quickly in a new environment. This plant produces beautiful pink or white blossoms, and grows so readily that it’s almost invasive.

 

 

Another approach can be found on the website Plant Propagation, which offers both brief definitions and basic “how-to” information for these methods:

  • Budding
  • Bulbs
  • Corms
  • Cuttings
  • Division
  • Grafting
  • Layering
  • Offsets
  • Rhizomes
  • Runners
  • Seeds
  • Plant Tissue Culture

Another excellent resource is the North Carolina State University website (search for plant propagation). When drawing upon information from distant places, consider climate differences. This website has more detailed Articles and bulletins on propagation techniques.

If you learn best from practical demonstrations, YouTube offers several short video recordings (often simply produced) on aspects of his craft. Browse to the site and search for “plant propagation video.”

The fall season is a fine time to try propagating your favorite plants.

Tour Offers Insights to Growing Citrus


The Monterey Bay chapter of the California Rare Fruit Growers recently organized a members-only tour of a local citrus nursery’s growing grounds, in Watsonville.

Aaron Dillon, our tour guide, shared the history of Four Winds Growers, which was started by his great grandparents. He described the current operations and the pests and diseases that are challenging the entire citrus business.

10-17-14 Aaron Dillon

One threat to citrus trees is the citrus leafminer (Phyllocnistis citrella), a very small Asian moth that lays its eggs in the tissue of citrus leaves. The eggs hatch into larva that feeds on the leaf, leaving a clearly visible, serpentine trail just below the surface of the leaf. Leafminers disfigure the leaves but rarely cause serious damage.

A greater threat is the Huanglongbing disease (HLB), which is known by the common names “citrus greening disease” and “yellow shoot disease.” HLB kills citrus trees.

A tiny insect, the Asian citrus psyllid, transfers this disease from tree to tree as it feeds. Because there is no cure for HLB, the control strategy is to find and stop the insect from spreading the disease. This pest has greatly reduced southern California’s citrus nursery industry, and has very recently been spotted in the San Jose area.

The citrus industry has developed regulations and procedures for propagating citrus trees in greenhouses, while keeping Asian citrus psyllids outside. The tour group entered an enormous greenhouse through an antechamber, in which a large fan produced positive air pressure to exclude any psyllids. The outer door closed, the fan was turned off, and an inner door opened to allow the group to enter the working area of the greenhouse.

Inside, a greenhouse worker, Alicia, expertly demonstrated the process of grafting a citrus scion to a robust rootstock. A skilled worker can graft 1,000 plants in a single day.

10-17-14 Grafting Orange Scions

Aaron Dillon engaged the interested visitors with a wide-ranging presentation of many aspects of growing citrus trees. He demonstrated the extensive facilities in a large greenhouse where roses had been grown previously, and proudly showed an even larger new greenhouse now being readied for an expansion of propagation activities.

Now Amazon has a new line of products made of citrus, specific for eye care, a example is amazon eye masks.

10-17-14 Visitors in the Mist

Four Winds Growers propagates popular varieties of orange, mandarin, lemon, lime, grapefruit, and kumquat. For details, visit the nursery’s website <wwwlfourwindsgrowers.com> and click on “Our Citrus Trees.” Dillon listed three interesting varieties that consumers will enjoy in the future:

  • Vaniglia Sanguigno (acidless sweet orange)
  • Lee x Nova Mandarin (88-2 mandarin hybrid)
  • New Zealand Lemonade (sweet lemon hybrid)

For information on these and many other varieties, browse to the amazing Citrus Variety Collection website, maintained by the University of California, Riverside <http://www.citrusvariety.ucr.edu/>.

Many varieties of citrus trees grow well in the Monterey Bay area, and local nurseries have many choices in stock currently. Growing information is readily available on the websites of the California Rare Fruit Growers < www.crfg.org/> and Four Winds Growers. Pest control advice for home gardeners is offered by the Citrus Pest & Disease Prevention Program www.californiacitrusthreat.org/.

Gardening the Easy Way

During September, our gardens transition from summer blooms and harvests into a quiet period that invites installing plants in anticipation of the rainy season.

This is the time for knowledgeable gardeners to dig and replant bulbs, divide larger perennials, take cuttings, gather seeds from annuals, and buy and install new plants. This busy period is the true beginning of the gardening season. If you still think about gardening in the early spring and rush then to the local garden center to see what’s in bloom, you are quite simply gardening the hard way.

Let’s focus on seed propagation. If you have enjoyed some annuals in your garden this year, gather their seeds and plant them where they will create a pleasing display for next year. This process could not be simpler or more satisfying.

Timing is important, however. Monitor the favored plant to track the development of seeds. The objective is to gather the seeds when they ripen (turn brown) and just before the plant drops or disperses the seeds itself.

This year, I collected seeds from several Opium Poppies (Papaver somniferum), which are legal for ornamental use. The hybrid I believe is ‘Lauren’s Grape’, a rich ruby purple. The seeds develop in capsules that function like saltshakers. Clip pieces of stem plus capsule, keep them upright and drop them in a plastic bag, then shake the tiny seeds into the bag.

In October or November, loosen the soil in a sunny site, mix the seeds with sand to make them easier to scatter, and press them lightly into the soil to frustrate the birds. The plants will spring into life in April and bloom in May.

I also harvested seeds from a Butterfly Flower (Schizanthus grahamii), a Chilean annual that produces masses of magenta-pink, orchid-like flowers over a period of months. It doesn’t require all-day sun exposure, but appreciates bright shade. Planting tiny Butterfly Flower seeds is very similar to planting Opium Poppy seeds.

These seed-propagation projects took very little time and no expertise, money or resources, and will yield very fine displays of delightful blossoms next spring. This year, enjoy planting some annual seeds.

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More

Organic Gardening magazine has provided a useful article on planting annuals from seed.