A plant that was given to me as a cutting has clear beads at irregular intervals along the stem. They are firm rather than sticky, but can be mashed between thumbnails. Is this insect- or disease-related, or something else? (The plant may be Abutilon but it has not flowered yet, so I am not sure.)
It is possible that these are ‘pearl bodies‘, also called ‘pearl glands’ or–if seen on grapes–‘grape balls.’ According to this scientific article, they are a type of food body (a nutrient-dense plant structure that offers food rewards to creatures such as ants). Other types of food bodies are extrafloral nectaries that secrete nectar, and domatia (chambers a plant produces to house ants or mites). Pearl bodies are part of a system of mutualism between plant and arthropod: ants gather the pearl bodies and take them to their nests, prompting the plant to form new ones in their place; in return, the ants may defend the plants against insect pests. Pearl bodies may be found on many different plants, particularly on a plant’s most robust branches.
We have a dead cherry tree in front of our house. We’re sad that it died since birds loved it and it bloomed starting early winter. We’d like to find someone to replace it for us and we’d like the new tree to be small to medium in size and be a draw for hummingbirds and other birds as the old cherry tree was.
What tree would you recommend to replace our old cherry tree?
We recommend you select a certified arborist to remove the dead tree. There is a list online here where you can narrow a search to your area.
There are some evergreen, flowering shrubs which appeal to hummingbirds, such as Grevillea, which can reach 8 feet tall, depending on the variety. Arctostaphylos (Manzanita) species and Abelia grandiflora are also possibilities.
Trees which are attractive to hummingbirds (according to Welcoming Wildlife to the Garden, by Catherine Johnson and Susan McDiarmid, 2004) include Malus species (crabapple), Crataegus (hawthorn), and Sorbus sitchensis (Sitka mountain ash).
Here are some websites with more suggestions:
Backyard Wildlife Habitat
WA Dept. of Fish and Wildlife Backyard Wildlife Sanctuary
USDA National Resources Conservation Service’s Backyard Conservation tips
What type of plant is the mistletoe people refer to during the holiday season? How did it get its name?
There are over 1,000 mistletoe species. It is a parasitic plant that was hosted by the oak tree, but also seen on pear trees in Roman times. Mistletoe has a long history of ritual use, myth, legend, and folklore. The name ‘mistletoe’ comes from two Anglo-Saxon words: mistle, meaning dung, and tan meaning twig. Why “dung on a twig,” you might ask. The name comes from the way the plant is propagated by birds eating the berries, then passing the seeds through the gut, and excreting the deposits onto the branches of trees. Seeds are rubbed around by the birds’ beaks when they wipe them on the bark. The seeds then germinate from cracks in the twigs of the tree. The species of European lore and legend is Viscum album, which lives on deciduous tree species, such as apple and poplar. In North America, mistletoe more commonly refers to Phoradendron leucarpum. You can watch a clip of birds interacting with an Australian mistletoe species on the BBC’s website. We also have in the library a copy of The Private Life of Plants by David Attenborough, which describes the phenomenon.
If you want to go deeper into the lore, we also recommend checking out The Green Mantle: An Investigation into our Lost Knowledge of Plants by Michael Jordan.
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.