Elisabeth C. Miller Library

Gardening Answers Knowledgebase

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Recently Added Questions

Question:

Why is the flower 'standing cypress' called that? It's obviously not a cypress (as in the tree). I am just curious about this great plant that brings all the hummingbirds and butterflies into my garden.

Answer:

Ipomopsis rubra goes by several other common names (Texas plume, red gilia, red Texas star, Spanish larkspur, and more). The common name you are wondering about may be derived from an impression of the feathery leaves echoing the foliage of true cypress (Cupressus) trees, though they more closely resemble Taxodium (bald or swamp cypress). 'Standing' is also puzzling, since these biennial flowers stand much less tall than a cypress tree. Maybe it is because when grown from seed, Ipomopsis forms a basal rosette the first year, and it doesn't 'stand up' and grow a tall spike until its second year.

Question:

I came across a reference to a "groundsel-tree" in a novel, and I wonder what its connection is to the weedy groundsel. In the book, it is found growing near the beach at Coney Island in the 19th century.

Answer:

The weedy groundsel is Senecio vulgaris (a Class C noxious weed in Washington State, with a more colorful common name, old-man-of-the-spring, presumably because of its fuzzy white seedheads), but 'groundsel tree' refers to a tree-like deciduous shrub, Baccharis halimifolia. It goes by other common names as well: sea-myrtle, saltbush, consumptionweed, silvering, coyotebush, and salt marsh-elder, to name just a few.

One obvious connection between the weed and the shrub is that they both belong to the daisy family (Compositae/Asteraceae). There is similarity in the shape of the flowers; according to Missouri Botanical Garden, the shrub's common name "refers to the similar appearance of the tufts of pappus on mature seedheads of this species and those of common groundsel (Senecio vulgaris)." (To me, Baccharis seedheads resemble the brushes on old-fashioned typewriter erasers!) Both plants have toxic properties. The weed is harmful if consumed by cattle or horses, and humans—though less likely to ingest it—can also suffer liver damage or death from eating it. The woody plant has toxic leaves and seeds. Both the weed and the shrub have the ability to spread aggressively, and according to this blog post from Buffalo Bayou Partnership, that trait is embedded in the common name groundsel, "from the Anglo-Saxon groundeswelge, meaning "ground swallower."

It makes sense that the plant would grow in a place like Coney Island (even in a fictional setting), because it is a salt-tolerant shrub. Baccharis halimifolia is native to the Atlantic and Gulf coastal areas of the eastern and southern U.S.

Question:

I planted three staghorn sumacs several years ago. They have done well, and have nice fall color, but I was hoping to see the flowers and fruit. This summer, for the first time, there are flowers on one shrub. What prompted the change? Will the flowering plant have fruit?

Answer:

Anecdotally, there are reports of Rhus typhina (staghorn or velvet sumac) taking a while to flower and fruit. If you don't have flowers on more than one of your three plants, you are not likely to get fruit (unless your flowering plant is female and someone nearby has a male, in case your other two are also female). Rhus typhina and Rhus glabra (smooth sumac) are dioecious, meaning that they produce male and female flowers (yellow green upright cone-shaped panicles) on separate plants. Plants of both sexes need to be grown together, and pollen from the male flowers needs to reach the female flowers, for the the upright clusters of the fuzzy disc-shaped dark red fruit (berry-like drupes) to develop on the female plants. These fruit clusters are colloquially referred to as 'bobs.'

You can examine the flowers on your plant closely (with a hand lens) to determine if they are male or female. Male flowers tend to be larger and have five yellow-tipped stamens, while female flowers have a three-lobed style in the center, and a calyx with five pointed lobes nearly the same length as the petals. Both flower stalks and calyx are densely hairy. [Source: Minnesota Wild Flowers field guide online] Here are additional photos to clarify the description.

Question:

I can't always tell rhododendrons and azaleas apart. Is there a way to distinguish between them?

Answer:

The answer is complicated because an azalea is also a rhododendron, but not all rhododendrons are azaleas! Furthermore, some azaleas are evergreen and others are deciduous. This information from the Azalea Society of America gives a few pointers.
Excerpt:
"Some small-leaved rhododendrons look like evergreen azaleas. To tell them apart, first look at a flower—most azaleas have only 5 or 6 stamens, while most rhododendrons have 10 stamens. Then look at a leaf—azalea leaves tend to be thinner, softer and more pointed than rhododendron leaves. Azalea leaves tend to have long straight hairs parallel to the leaf surface, usually along the midrib on the underside of the leaf. Finally, using a magnifying glass, look at the underside of a leaf for tiny round structures called scales. Azalea leaves never have scales, while small-leaved rhododendron leaves are always covered with scales. (The more correct name for small-leaved rhododendrons is 'lepidote' rhododendrons, where lepidote means 'covered with scales')."

In case you are curious, evergreen azaleas were first cultivated in Japan over 400 years ago (according to Christopher Fairweather, in his book Azaleas, Globe Pequot Press, 1988). These were the evergreen azaleas. The first azaleas in European gardens (starting in the 17th century in Holland) were deciduous, and they were endemic on three continents (particularly from Turkey, the Far East, and both coasts of North America).

There is a taxonomic explanation in Fred C. Galle's book, Azaleas (Timber Press, 1987):
"The genus Rhododendron was first recognized by Linnaeus in Species Plantarum in 1753. Linnaeus created a separate genus Azalea containing six species. In 1834, George Don [...] subdivided Rhododendron into eight sections which are botanically retained today. Azalea was included under the genus Rhododendron by Don. In 1870. Dr. C. J. Maximowicz made a major contribution in the classification of Rhododendron and many oriental Azalea based on the position of leaf bud in relation to flower buds. More recent classifications reflect refinement rather than major changes. [...] The question of splitting Azalea into a separate genus came up as late as 1943, but it is hoped that this classification will never be accepted."

Question:

As an avid plant person who is also a metalsmith and jeweler, I was surprised to learn that we get the weight measure for stones (carat) from the ancients who used carob beans as a standard weight. Because "carob beans are unusually consistent in size. This means that carob beans usually all weigh the same, no matter when or where harvested!"

My mind is reeling! How can that be? Nature doesn't do that! Every plant is unique, I thought, weather, soil, location should change the harvest, I thought. Am I mistaken?

Answer:

On that last point, you are not mistaken: there is variability in the weight of carob seeds, but it is relatively small. Ceratonia siliqua is in the bean/legume family [Fabaceae]. It is not the elongated carob pod that was used as a standard, it's the seeds contained in that pod ( a typical pod contains about 10 seeds). Seeds from female trees are relatively consistent (0.197 grams or 1/150th of an ounce). This weight was standardized to 200 milligrams in 1907, and continues to be in use.

The scientific paper Seed size variability: from carob to carats (Turnbull et al., 2006, Biology Letters: The Royal Society, published online 2006 May 2) attempts to explain the "myth of constant seed weight." As far back as ancient Greece, there was a weight called a kerat (which is echoed in carob's Latin genus name, Ceratonia). Keration was the Greek word for carob (possibly a Semitic loan word from Aramaic/Syriac karta meaning pod or husk), and its literal meaning was 'little horn,' which describes the shape of the pods (not the seeds). Siliqua, carob's species name, was the Latin word for carob, and used to refer to the smallest subdivision of the Roman pound. Carob seeds were no more consistent in mass than the other 63 species the article's authors measured. They theorize that seeds used for weighing were a product of human selection.

Carob thrives in its native Mediterranean and Middle Eastern regions, and would simply have been readily available as a counterweight for precious substances, like gemstones and spices. Humans can perceive mere 5% differences in carob seed mass. In the ancient world, measurement of weight based on carob seeds would have been fairly dependable, based on the accuracy of the human eye—unless an unscrupulous vendor also kept sets of seeds that were heavier or lighter than the standard, either to shortchange or overcharge!