propagating Phalaenopsis orchids

I have a question about a Phalaenopsis orchid. The orchid is a year old and at the top of last year’s flower stalk has grown a new set of leaves as well as roots. Can this be cut off and re-rooted? Also, after the blooms fade, do you cut the stalk off and if so, how far?

Here is some information on propagation of Phalaenopsis, from a commercial orchid grower:

“Phalaenopsis can be vegetatively propagated by cutting the flowering stem above a stem internode, the dormant growth ‘eye’ is covered with a triangular sheath. Cut, with a hot knife or shears, through the flower stem after the last flower has fallen. Then move the plant to a dimmer area. In most cases, new plants will start from the dormant ‘eyes.’ After the new plants initiate, the mother and ‘keikis’ (babies) can be move gradually back to higher light. When the keikis have 2-3 roots, the keikis can be removed, by slicing between the stem and the keiki, or cutting the stem above and below keiki’s attachment point. The new plant can now be potted up and grown on. If more flowers are desired, cut the stem as above, but do not move the plant. In the second method, the mother plant is topped. As a monopodial plant, Phals continue to grow vertically. In time, they discard their lower leaves. The leaves have served as a storage vessel of water and nutrients. The leaves have outlived their usefulness and are discarded. New roots are produced above the leafless stem, as the Phal continues growing vertically. The stem can be cut below the new roots. The top part, with leaves and roots, can be repotted after proper care of the cut. The remaining stub can be left as is, for a few days/weeks. Soon, new little plants will be found growing out of the old stub. These keikis can be repotted in the same manner as the first method. They will grow on and eventually bloom. If left on the stub, they will often bloom sooner, than if individually potted.”

The American Orchid Society has a video illustrating the potting of a keiki, as well as a host of other orchid care information.

You may find the following links to the Brooklyn Botanic Garden useful for general directions on orchid care. Here is an excerpt:
“Some species will also produce plantlets on the flowering spikes, complete with leaves and roots. These small offshoots can be pruned and planted, but keep in mind that transition from plantlet to flowering specimen is a long process requiring several years and lots of patience.” Here is another helpful link from the Brooklyn Botanic Garden website.

As for what to do with a spent flower stalk, here is what the Royal Horticultural Society recommends: “A flower spike can continue to bloom for up to three months. Once faded, cut the spike just above the second node (joint) beneath the spent flowers, and a flowering sideshoot may develop.”

hummingbirds and plants’ supply of nectar

I would like to know how the hummingbird’s feeding affects the level of nectar in flowers. I already know about which flowers produce nectar that will attract hummingbirds. My main concern is whether hummingbirds can use up a plant’s supply of nectar.

There has been some research which suggests that a plant’s production of nectar is regulated by hormones. Sometimes the hormone attracts one creature in order to repel another. The article excerpted below suggests that rapeseed plants produce nectar to attract ants that will defend them against caterpillars. Source: Max Planck Society for the Advancement of Science (March 29,2010):
“Jasmonic acid and related molecules are constituents of molecular signal transduction chains in plant tissues. These compounds – generally referred to as jasmonates – are synthesized when caterpillars feed on plants; they are signalling substances and belong to the group of plant hormones. By producing jasmonates the plant regulates its defence against herbivores e.g. by stimulating the synthesis of toxins. Moreover, previous studies have shown that jasmonates regulate the production of “extrafloral nectar”. This particular nectar, which is produced by special glands called “extrafloral nectaries”, has nothing to do with pollination, but attracts ants to the herbivore-attacked plants as defenders against their pests. The sugars in the nectar reward the ants for defending the plant. The same principle applies to floral nectar: nectar production in the flowers attracts and rewards pollinators which in turn contribute substantially to the seed yield. However, up to now, it has not been clear how nectar production is regulated in the flowers.”

In the book The Biology of Nectaries edited by Barbara Bentley and Thomas Elias (Columbia University Press, 1983), there is an essay called “Patterns of nectar production and plant-pollinator co-evolution” (by Robert William Cruden et al.) which states that “flowers pollinated by high-energy requiring animals [this would include hummingbirds] produce significantly more nectar than flowers pollinated by low-energy requiring animals, such as butterflies, bees, and flies.”

Similarly, plants whose pollinators are active in the day produce more nectar during the day, and plants pollinated by nocturnal creatures will make more nectar at night.
So clearly there is an intricate system of response between the needs of the plants and the needs of the hummingbirds, and the biology of individual plants has evolved to serve the plants’ interests which are tied to those of pollinators. In effect, the hummingbird can’t exhaust the nectar supply of the flowers, because the plant has adapted to meet its needs.

on shade gardening

Which flowers can be planted in the shade?

The University of Minnesota Extension Service article entitled, “Gardening in the Shade” provides lists of annuals, perennials and herbs that do well in the shade.

Gardening with Ed Hume offers advice about growing plants in shady areas under tall trees.

For resources specific to the Pacific Northwest, try the list of shade perennials from Paghat’s Garden, Great Plant Picks, King County’s searchable Native Plant Guide, and lists of native plants for mostly to fully shady sites Washington Native Plant Society. There are also numerous books available in the Miller Library. Here is a booklist.

aquatic plants and water gardening

I am looking for information about planting floating emergent plants (e.g., water shield, yellow pond lily) in natural ponds. If planting young plant material in the soil, what is the recommended water depth? Is it okay to submerge the entire shoot? If yes, what is a safe depth from top of shoot to water surface?

There are several different types of plants that are grown in ponds. A great resource on planting floating plants is The Water Gardener’s Bible: A step-by-step guide to building, planting, stocking, and maintaining a backyard water garden by Ben Helm and Kelly Billing (Rodale Inc., 2008). In the book they explain that floating plants will either float on the pond surface or be slightly submerged. The most popular floating plants are Frog’s bit (Hydrocharis morsus-ranae), Water hyacinth (Eichornia crassipes), Water chestnut (Trapa natans), and Water soldier (Pistia stratiotes). They also explain submerged plants that will inhabit a pond at all levels, from those whose roots sit on the bottom to those that emerge from the pond, getting only their feet wet. For planting a water lily, place on a stack of bricks in the position where the lily will be sited, so that the top of the planted basket is no more than 1 inch (3 cm) below the surface. As the leaves start to extend, remove the bricks until the basket is on the pond bottom.

Another great book is Plants for Water Gardens: The Complete Guide to Aquatic Plants by Helen Nash and Steve Stroupe (Sterling, 1998). The book contains a huge list of a variety of lily plants and specifications for planting and survival.

Texas A & M Extension has a website on water gardening with useful information on planting aquatic plants. You may want to check your local list of invasive species before planting.

on bracken fern

My question has to do with the fall/winter foliage of bracken fern (Pteridium aquilinum). A friend trimmed the bracken to the ground. Will the bracken grow back next spring? This led to other questions. Does bracken lose only its leaves in the winter or does the entire plant die off? Does it spread through its roots or spores? Any information you have would be appreciated.

Bracken is deciduous, that is, the fronds die to the ground in winter and then regrow from the rhizomes in the spring. If your friend cut her bracken down to the ground late in the year there would be no problem. Even if it was earlier in the year, the bracken would probably survive. According to the fern books I read, people have tried mowing to remove their bracken with no success. The books also warn that bracken is very invasive and not recommended for small gardens. It spreads by underground rhizomes, maybe by spores as well, and can take over a large space in a very short time.

It might be a good idea to take a look at some pictures either in books or online (just enter the name in Google and select Images above the search box) to make sure this is what your friend has. Any deciduous fern (and even some evergreen ferns) can be cut to the ground in fall, but generally it is better to wait until the new fronds appear in spring to cut out the old fronds of evergreen ferns.

The USDA Plants Database provides further information.

Sources consulted:

The Plantfinder’s Guide to Garden Ferns (by Martin Rickard, 2000)
Ferns to Know and Grow (by F. Gordon Foster, 1984)

on corn-gluten based weed killers

What can you tell me about the weed killer “Concern Weed Prevention Plus”?

This product is corn-gluten based, and it is not meant to work on weeds which are already growing, but on those which have yet to emerge (pre-emergent). Corn gluten meal has been promoted as an environmentally safer alternative to conventional herbicides, but there are still certain issues that bear considering. Research at Oregon State University showed that corn gluten meal did not prevent weed seed germination. Here is an excerpt from the study’s findings:
“Corn gluten meal did not control any weeds in any trials under any circumstances over a two-year period. They found no evidence of pre- or post-emergence weed control in any of their trials. Because it contains 10 percent nitrogen, corn gluten meal proved to be a very effective fertilizer, causing lush, dense growth of turfgrass and of weeds in shrub beds.”

Although corn gluten meal presents far fewer risks to human and animal health than conventional herbicide, a gardener who is attempting to use only organic methods might consider the source of the corn in these products, which is very likely to be genetically modified. A webpage no longer available from University of Wisconsin Master Gardeners addressed this question:
“Up to 60% of the commercial corn and soybeans in the United States is grown from GMO seed. Corn gluten sold as a preemergent herbicide may indeed contain GMO corn, but it has not yet been tested. Here’s the twist. Corn gluten can reduce the need for traditional herbicides that have environmental side effects. It likely now contains GMO corn. It could be produced from non-GMO corn, but would likely be more expensive.”

Washington State University professor of horticulture Linda Chalker-Scott has also written about “The Myth of Weed-Killing Gluten,” and states that no research suggests this is an effective method of weed control in the Northwest. She recommends sub-irrigation, mulch, and soil solarization instead.

management of Poa annua

Is there a preemergent to use on Poa annua grass in the lawn and if so what is the name and when should it be applied?

According to The Lawn Bible by David R. Mellor (Hyperion, 2003), your best defense against Poa annua (annual bluegrass) is to mow high (2 inches, usually) to shade out weed seedlings; aerate the soil to improve drainage, because weeds thrive in waterlogged soil; and let the surface of the soil dry out between waterings. If one were to apply preemergent herbicide, this would be done in late summer to early fall, but we strongly recommend that you avoid use of herbicides and pesticides in lawn care due to environmental and health concerns. There are effective non-toxic approaches to weed management. Northwest Center for Alternatives to Pesticides has useful information on maintaining a lawn without chemicals.

For another good discussion of this issue, you might want to refer to the book, What the Experts May Not Tell You about Growing the Perfect Lawn by Tom Ogren (Warner Books, 2004).

The University of California, Davis Extension has a document about the management of Poa annua, including specific information on the various herbicides that have been used to treat it but, as mentioned before, it is best to avoid the use of toxic chemicals in the garden.

on gardening near septic system drain fields

Here is the situation: I have six inches between the cement wall and the septic drain field. I want a green screen between myself and the neighbors on the other side of the short cement wall. What can I grow that will give me a green screen and not invade the septic system pipes? All I can think of is some sort of climbing vine, but I am not familiar with which root systems could be a problem.

You have a real challenge with your situation. Most of the literature says that you should not plant any large shrub or tree within 30 feet of a septic system drain field.

Roots growing into the drain field is a serious concern. They recommend consulting an expert if you do want to plant near a drain field.

Instead, you might consider installing an attractive fence and/or using containers to grow plants in. For example, Camellias can be grown on a trellis from a container. They are evergreen, and will also flower.

Another vine-like plant is star jasmine, Trachelospermum jasminoides. It is evergreen with fragrant white flowers.

conifers with low root damage potential

Can you suggest any larger growing conifers (ex. Lawson’s cypress) whose root systems are not invasive? The area I’m interested in planting is near water lines.

There are a number of conifers listed on the locally developed web pages of
Great Plant Picks.

I would suggest looking at some of these, and then checking the web page of
SelecTree, where you can select trees for low root damage potential.

For instance, if you are interested in planting a fir tree such as Abies
grandis or Abies pinsapo, you would find out from SelecTree’s full tree
record that both of these have moderate root damage potential. Calocedrus,
Picea orientalis, Sequoiadendron and Cryptomeria are also rated as moderate.
Cephalotaxus fortunei is rated low, as are Pseudotsuga menziesii, and
several Chamaecyparis species. The following conifers rated as having high
root damage potential:

Picea abies NORWAY SPRUCE

Picea brewerana BREWER’S WEEPING SPRUCE

Pinus cembra SWISS STONE PINE

Pinus nigra caramanica CRIMEAN PINE

Pinus taeda LOBLOLLY PINE

caring for Echeverias

I have a start from a large hen & chicks (Echeveria). I have seen these plants grow up to 6 feet tall like a shrub. My start is over two years old. It takes off and seems to thrive, but never gets tall or hardy. It seems to go a year and then the outer leaves wilt. Once it got big enough to tip over, so I am wondering how to give it the right pot and correct soil to allow it to grow. It is located in our west sun room here in the great northwest. Is it alright outdoors in the summer?

I wonder if you have information about the particular species of Echeveria you are growing. Usually, ‘hens and chicks’ is the common name for Echeveria glauca. The larger growing Echeveria are the ones with “loose, cabbage-like rosettes which reach a foot or more in diameter on heavy stems” (from The Book of Cacti and Other Succulents by Claude Chidamian, Timber Press, 1984).

I consulted Victor Graham’s book, Growing Succulent Plants (Timber Press, 1987) for some general guidelines on the best growing practices for Echeveria. He says that the soil you provide should be gritty and on the poor side (for good drainage), and they should not be overfed. In The Succulent Garden: A Practical Gardening Guide by Yvonne Cave (Timber Press, 1997), the recommendation for areas with wet winters such as ours is to grow them in containers on a covered porch or in any sunny spot with overhead cover. In the warmer, drier months they can be placed or planted in the garden without cover. Your sun room sounds like a fine place to grow them during the winter here, although they may prefer morning sunlight and afternoon shade to bring out the best color in their leaves.

The Brooklyn Botanic Garden has a page on growing succulents that may be useful.