bioluminescence and plants that emit light

I live in Nigeria. There is a plant, I don’t know the name, but I know some of its characteristics: mostly it grows near rivers or rocky areas, sometimes it flashes light in the night like a firefly, and there are red ants that climb it. Can you tell me what plant this is?

We certainly aren’t experts on the flora of Nigeria, but what you are describing could be bioluminescence. There are definitely fungi which are bioluminescent, and it’s possible the plant you are describing is host to a fungus (such as Armillaria, Omphalotus, Tricholomopsis, or Clitocybe) which does glow or emit light in the dark. The less scientific name for this phenomenon is ‘foxfire.’ The University of California, Santa Barbara maintains a web page on bioluminescence, and answers commonly asked questions about it. Here is an excerpt:

“There are not any luminous ‘flowering’ plants which have been discovered. (That would be neat if rainforests glowed, but I think it is only likely to happen if they have something else on the vegetation in there making the light). Fungi, some of which do luminesce, are not plants, and so they don’t qualify. The only ‘plants’ which do make light are the dinoflagellates, single-celled marine algae, and they are not plants strictly speaking.”

Although I seriously doubt this is what you are seeing, there is some work being done currently on developing artificially luminescent trees (using nanotechnology and genetic engineering: ). As mentioned above, plants are not naturally luminescent themselves, though they may be host to luminescent fungi and bacteria.

Another plant that I thought of is Dictamnus, which is referred to as the ‘gas plant,’ because it exudes a volatile oil which is flammable and can be ignited with a match. Although I haven’t heard of ants being interested in this plant, it would make some sense, because ants would probably be attracted to plant oils (just as they are attracted to nectar, or to ‘honeydew’ secreted by other insects on plants).

If you could send pictures of the plant you have noticed, include close-ups so that any fungal presence on the plant would be visible. That might be helpful in identifying it and determining the cause of the firefly-like flashes of light. The other consideration is that Nigeria has a high number of gas flares in the river delta which could also look like flashes of light at night.

vegetables for a short growing season

I have set up four-by-eight-foot raised vegetable beds in the only available spot in my backyard (here in the Pacific Northwest). In winter, the house casts its shadow over the entire bed area. With the progress of the seasons, the shadow recedes and leaves the beds entirely in the sun only by approximately mid-May. Similarly, the house shadow again begins to encroach on the bed area by the beginning of August.

What can I grow with this ultrashort growing season? What vegetables, if any, are likely to succeed here?

It sounds like you have about 75 days of well-lit growing season. The Maritime Northwest Garden Guide by Lisa Taylor (Seattle, WA: Seattle Tilth, 2014) lists several varieties of vegetables come to harvest within 75 days in our
area, and here’s what I see:

carrots
swiss chard
cress
kohlrabi
lamb’s quarters
lettuce (if picked young)
arugula
spinach
summer squash
turnips
purslane
shungiku (edible chrysanthemum)
swiss chard
kale
tatsoi
bok choi/pac choi

In 10 Terrific Vegetables, produced by the National Gardening Association, the author suggests that vegetable gardens require at least 6 hours of sun per day (South Burlington, Vt. : National Gardening Association, 2002). Some fast-maturing vegetable varieties listed include ‘Green Comet’ Broccoli (40 days) ‘Packman’ broccoli (53 days), Kentucky Wonder beans (60 days), Romano beans (75 days), basil (70 days), ‘Amsterdam’ and ‘Nantes’ carrots (60 days), ‘Sugarsnap’ peas (62 days–and they should be planted earlier, before the soil warms), ‘North Star’ red pepper (60 days), ‘Melody,’ ‘Space,’ ‘Tyee,’ and ‘Bloomsdale Longstanding’ spinach (all under 45 days), ‘Sun Gold’ tomato (57 days).

In general, you can find the number of days to maturity listed on the back of seed packets, so you can check if the varieties you want will ripen in time. Another quick-harvest vegetable is the radish, which can be ready to eat in just a few weeks. I’ve also had some luck with potatoes in less-sunny locations, although they do take a fair amount of space.

You might also consider growing raspberries, which don’t need sun quite as much as vegetables, in one of your beds.

reviving construction-damaged trees

We have some Douglas Fir trees along a ravine. There is some construction nearby, and one of the trees is looking like it has been affected. It’s losing lower branches and has much less new growth than its neighbors that are farther away from the construction. Is there anything we can do to save it?

It certainly could be compaction, though it is not possible to diagnose from a distance. However, symptoms of soil compaction damage include drooping branches, wilted or scorched foliage, and conifers dropping inner needles. This came from the Minnesota DNR’s web site, which also discusses treatment. Here is an excerpt:

“Compaction can be partially alleviated by drilling a series of two inch diameter holes to a depth of 12 to 18 inches. Begin three feet from the trunk and continue drilling holes at two foot intervals in concentric rings around the tree and continue to at least the dripline. Each hole may be refilled with sand, peat moss or mulch. Don’t recap the hole with a sod plug. There are other alternatives, such as soil injections of air or pressurized water, available from some professional tree care services.”

A WSU extension formerly available online (“Construction Damage to Trees”) explains that careful watering and fertilizing can help damaged trees, though it is best to help them before damage is noticed.

Another good resource is the Colorado State University Extension’s “Protecting Trees during Construction.”

Finally it would be a good idea to consult the Plant Amnesty referral service at 206-783-9813, or search for an arborist at the PNW International Society for Arboriculture site under “Hire an Arborist.”

propagating yew from cuttings

I planted a Taxus baccata ‘Fastigiata’ roughly 10 years ago and it grew to about 1.5m. Unfortunately it was cut down by mistake. Is there any way I could take a cutting from the tree or some way to preserve any part of it? It holds great sentimental value.

According to The Complete Book of Plant Propagation, edited by Charles Heuser (Newtown, CT: Taunton Press, 1997), your yew can be propagated by cuttings, but it is recommended that the cuttings be taken in fall. It’s worth a try to take some now, though, since the tree is already cut. You want upward-growing, semi-ripe cuttings (that is, there should be some bark at the base and some green stem at the tip), and they should be pulled off with a downward motion so that you get a “heel” of bark from the main shoot. Treat them with rooting hormone and place in a pot somewhere where it can remain cool and moist for several months. Take plenty of cuttings to increase your chance that at least one will survive.

American Horticultural Society’s Plant Propagation, edited by Alan Toogood (New York: DK Publishing, 1999), has more specific suggestions. They suggest a 4-6 inch cutting from 1-3 year old wood that is still green at the base.

If your yew made seeds, you might try planting them, but it takes a long time for them to germinate and grow from seed. To grow from seed, the AHS Plant Propagation recommends mixing the seeds with damp peat or sand and keeping them at about 68 degrees for 4-6 months, then at 34 degrees for 1 month before planting. If the seeds germinate in late summer, though, they won’t be ready to winter outdoors that year. For this reason, the AHS also suggests simply sowing the seeds outdoors and waiting for germination in 1-2 years. If you do this, be careful not to lose your sown seeds while waiting for them to grow!

cracks and splits in tree trunks

The bark on our apple tree has split, approximately 24″ vertically, revealing the wood of the tree underneath. Is there anything we can do to protect it and help it heal itself? If it were a wound, we’d get stitches for it, but we’re afraid to make it worse by wrapping the wrong thing around it.

It is possible your tree’s bark split open due to weather extremes (frost cracking or sunscald), or uneven growth. Sometimes it is recommended to score the edges of the split with a sharp tool, but I don’t recommend it here because of the length of the split on your tree. Cornell University describes the procedure, however.

According to a following discussion on North American Fruit Explorers, it may be possible to leave split bark to heal on its own.

Missouri Botanical Garden offers the following information on cracks and splits in trunks:

Excerpt:
“Cracks and splits in tree trunks are fairly common and may occur for various reasons, but are usually not a significant threat to the tree. Typically, there’s not much you can do about them once they occur. They do, however, occasionally signal a serious problem that may eventually kill the tree.

“One of the most common reasons for cracks and splits on tree trunks is frost cracking. Frost cracks occur during cold winter weather. The inner and outer wood in a tree’s trunk expands and contract at different rates when temperatures change. When winter temperatures plummet below zero, especially after a sunny day when the tree’s trunk has been warmed by the sun’s rays, the different expansion rates between the inner and outer wood can cause such a strain in the trunk that a crack develops. Frost cracks occur suddenly, can be several feet long, and are often accompanied by a loud, rifle-shot sound. Frost cracks at a point where the trunk was physically injured in the past.

“Maples and sycamores are very prone to frost cracks. Apples, ornamental crabapples, ash, beech, horse chestnut, and tulip trees are also susceptible. Isolated trees are more subject to frost cracks than trees in groups or in forest settings. Trees growing on poorly drained soils are particularly prone to frost cracks.

“Frost cracks often close during summer, only to re-open in succeeding winters. They do not seriously damage trees, although they do provide openings where certain disease organisms may enter the tree, particularly if the tree is in a weakened condition. Frost cracks are difficult to prevent. Wrapping the trunks with tree wrap paper in fall helps, but is inconvenient to do year after year. Apple growers sometimes white-wash the trunks of apple trees to prevent frost cracks and other winter injury problems, but this is unattractive in landscape settings. The best way to prevent frost cracks is to prevent any injuries to the trunk throughout the tree’s life. A professional arborist can bolt frost cracks shut with a technique called lip bolting. Most people simply remove loose bark hanging along the edges of the crack. You should not paint frost cracks or other wounds with tree wound dressing. These materials can trap moisture, causing decay in the trunk.”

dealing with hogweed plants

I have three fast-growing hogweed plants in my backyard, but a garden designer at City People’s warned me not to tackle them before consulting someone at the Center for Urban Horticulture. She said hogweed is nasty, and it certainly looks so.

If you do have hogweed (Heracleum mantegazzianum), it is a Class A noxious weed (eradication required by law in King County and the State of Washington). You should contact the King County Noxious Weed Control Program to report it using their Infestations Form.

The folks at City People’s were right to tell you not to touch it, as the sap is considered a public health hazard. Any skin exposed to it will become extremely sensitive to sunlight. King County provides more information about the effects.

You can find out more about the history of this invasive in North America (including a song!) at the site E-Flora B.C.

plants that tolerate black walnut

I would like a plant list of plants that are resistant to the juglone toxin.

Juglone, a toxin produced by walnuts (Juglans spp.), can be a problem for many plants. Luckily, some don’t mind it.

Here is a list of juglone-tolerant and juglone-sensitive plants, from University of Wisconsin
Urban Horticulture.

Virginia Cooperative Extension also has a list.

Ontario’s Ministry of Agriculture has similar information.

inadequately decomposed materials in compost

I bought compost from the city of Port Angeles and in a sifted wheelbarrow of compost I got three gallons of pencil diameter “twigs”. These are not composted. They break/snap and are green inside. The compost was supposed to be tilled into the garden and flower beds but somewhere in the back of my mind I sort of remember that this will take nitrogen out of the soil to compost down. Is that correct or should I not be concerned?

It sounds like screening your compost was a good place to start; Mike McGrath recommends removing the “odd original ingredient” from compost this way in his Book of Compost (New York, NY : Sterling Pub. Co., 2006). Woody material should definitely be removed, he says. If your compost does not seem otherwise ‘off’ (an ammonia smell, a sulfurous smell, very odd color), sieving off the woody material is often sufficient.

Twigs compost more slowly than other material, and you could, if you like, simply re-compost them, according to the King County Solid Waste Division.

There is some debate over the effects of inadequately decomposed material such as your woody twigs in compost and mulch. Linda Chalker-Scott addresses the question of less-than-fully composted yard waste in her May 2003 myth. She agrees that inadequately decomposed yard waste has a reputation of removing nitrogen from the soil, but writes that the way the yard waste is used affects the way it interacts with the soil. As a mulch (a layer over the soil to prevent weeds or retain moisture), it does not significantly reduce soil nitrogen, but as a compost (incorporated into the soil), it may reduce nitrogen in the soil.

If you are still concerned about the quality of your compost, Stu Campbell suggests using the following techniques on municipal compost in his Mulch It! (Pownal, Vt. : Storey Books, 2001) First, test the pH, and, if it is off, store and turn the compost for several months before using it. Mature compost should have a pH between 6 and 8,
which you can test using a soil test kit or some of the other options listed on Cornell University’s composting pages.

tree topping

The previous owners of our home planted Leyland Cypress at the property line. The trees have grown very high. The neighbors have asked us to trim these trees in a “hedge-like” fashion, which means that we would need to cut the tops of the trees. One neighbor, who is a landscaper, insists this will not damage the trees. But several arborists have advised not to “top” the trees. We are willing to have the trees topped as long as this will not compromise the health of the trees.

Pruning Leyland Cypress (x Cupressocyparis leylandii) to look like a hedge can be a challenge.

Topping is not a recommended method for controlling trees, because it often causes them to grow faster (unless they are topped mortally) and thus must be done repeatedly and expensively, and also because it weakens the tree, which may cause it to drop limbs, rot, or blow over more easily. The group Plant Amnesty has a great deal of information about why one should avoid topping.

However, topping may be less harmful for x Cupressocyparis leylandii than for other plants, but it is still not a particularly effective solution. The University of Florida Extension concurs that this practice is less harmful
to x Cupressocyparis leylandii than it is to other species, but they still do not recommend it.

Peter McHoy’s A Practical Guide to Pruning (New York: Abbeville Press Publishers, 1993) also advises avoiding topping, but also notes that if one must top an x Cupressocyparis leylandii, it should be done in midsummer and repeated every few years.

However, in general, it would appear that topping is very much a last resort.

One book, Practical Tree Management: An Arborist’s Handbook, by T. Lawrence, P. Norquay, and K. Liffman (Melbourne: Inkata Press, 1993), recommends that “Where a tree requires severe reduction or radical alteration
of its aesthetically pleasing, natural growth habit, it is usually far better to consider replacing the tree with a species more suitable for the situation…” Thus, you may consider an initial pruning and eventual replacement.

controlling whiteflies and recycling grass clippings

I have whiteflies on my orchid Christmas Cactus. How can I get rid of them? I also would like to know if grass clippings are good to fertilize raspberries.

Christmas cactus, or Schlumbergera bridgesii, does occasionally have problems with insects. Whitefly nymphs and adults cause damage by sucking plant juices, and their feeding can weaken a plant. They also secrete a sticky substance called honeydew, which may then harbor sooty mold. For indoor plants affected by this insect, you might try gently washing the leaves. Rodale’s Encyclopedia of Indoor Gardening, edited by Anne Halpin (1980) says that adults are easy to wipe up when it is colder indoors, and the young are usually on the undersides of leaves and may be wiped off with a sponge. Many whiteflies are now resistant to insecticides, and so it is best to start with plain water or soap and water. The book Indoor Gardening the Organic Way by Julie Bawden-Davis (Taylor, 2006) lists sticky traps, insecticidal soap, alcohol spray, oils, and pyrethrin as potential controls. There are products containing Neem oil which could help, if plain water or soapy water don’t control the problem.
Clemson University Extension has some helpful information on general care of this plant.

As for using grass clippings as fertilizer, as long as the grass was not treated with weed-and-feed or other pesticides, it should be a good source of nutrients. Also, avoid using grass which has already gone to seed. Mulch It! by Stu Campbell (Storey Books, 2001) advises not to spread the clippings too thickly, and to let them dry out a bit before using. Here is a link to Virginia Cooperative Extension’s page on recycling grass clippings.

Taylor’s Guide to Fruits and Berries edited by Roger Holmes (Taylor, 1996) says that “reasonably good soil enriched with an inch or two of good compost or a moderate dose of balanced fertilizer each year should provide sufficient nutrients for your plants to thrive. Berry lovers sometimes provide regular doses of foliar fertilizers to give their plants a boost. Absorbed by the leaves in liquid form, seaweed, fish emulsion, and similar organic materials in balanced formulations provide a broad spectrum of nutrients.”