You are looking at all articles with the topic "Horticulture and Gardening". We found 7 matches.

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A ha-ha (French: hâ-hâ or saut de loup) is a recessed landscape design element that creates a vertical barrier while preserving an uninterrupted view of the landscape beyond.

The design includes a turfed incline that slopes downward to a sharply vertical face (typically a masonry retaining wall). Ha-has are used in landscape design to prevent access to a garden, for example by grazing livestock, without obstructing views. In security design, the element is used to deter vehicular access to a site while minimizing visual obstruction.

The name "ha-ha" is thought to have stemmed from the exclamations of surprise by those coming across them, as the walls were intentionally designed so as not to be visible on the plane of the landscape.

Atomic gardening is a form of mutation breeding where plants are exposed to radioactive sources, typically cobalt-60, in order to generate mutations, some of which have turned out to be useful.

The practice of plant irradiation has resulted in the development of over 2000 new varieties of plants, most of which are now used in agricultural production. One example is the resistance to verticillium wilt of the "Todd's Mitcham" cultivar of peppermint which was produced from a breeding and test program at Brookhaven National Laboratory from the mid-1950s. Additionally, the Rio Star Grapefruit, developed at the Texas A&M Citrus Center in the 1970s, now accounts for over three quarters of the grapefruit produced in Texas.

Garden hermits or ornamental hermits were hermits encouraged to live in purpose-built hermitages, follies, grottoes, or rockeries on the estates of wealthy landowners, primarily during the 18th century. Such hermits would be encouraged to dress like druids and remain permanently on site, where they could be fed, cared for, and consulted for advice, or viewed for entertainment.

Botanical sexism is a term coined by horticulturist Tom Ogren to describe the planting of male plants instead of female plants of certain dioecious species including: willows, poplars, aspens, ashes, silver maples, pistache, mulberry, pepper tree and other woody plants such as junipers, yew pines, fern pines, wax myrtles, alpine currants, plum yews, and yews According to Ogren, pollen allergies have been amplified due to the planting in urban areas of male clones which increases the amount of pollen in the air. Male plants are commonly used in urban areas because plants with female flowers produce fruits and flowers that litter the landscape. The planting of more female plants would decrease the overall amount of pollen since they do not produce pollen and remove pollen from the air for pollination. The theory has existed since at least the 2000s. Biological sexism is used in the Ogren Plant Allergy Scale (OPALS), which has been adopted by the United States Department of Agriculture. Botanical sexism has found some scientific acceptance as a reason for increased allergies and asthma; however, other scientists have also been critical of it, stating that it only applies to certain trees and is not as widespread as Ogren alleges.

Hügelkultur (German pronunciation: [ˈhyːɡl̩kʊlˌtuːɐ̯]), literally mound bed or mound culture, is a horticultural technique where a mound constructed from decaying wood debris and other compostable biomass plant materials is later (or immediately) planted as a raised bed. Considered a permaculture practice, advocates claim that the technique helps to improve soil fertility, water retention, and soil warming, thus benefitting plants grown on or near such mounds.

Axel Erlandson (December 15, 1884 – April 28, 1964) was a Swedish American farmer who shaped trees as a hobby, and opened a horticultural attraction in 1947 advertised as "See the World's Strangest Trees Here," and named "The Tree Circus."

The trees appeared in the column of Robert Ripley's Believe It or Not! twelve times. Erlandson sold his attraction shortly before his death. The trees were moved to Gilroy Gardens in 1985.

The nematodes ( NEM-ə-tohdz or NEEM-; Greek: Νηματώδη; Latin: Nematoda) roundworms or eelworms, constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a broad range of environments. Most species are free-living, feeding on microorganisms, but there are many that are parasitic. The parasitic worms (helminths) are the cause of soil-transmitted helminthiases.

They are taxonomically classified along with arthropods, tardigrades and other moulting animals in the clade Ecdysozoa. Unlike the vaguely similar flatworms, nematodes have a tubular digestive system, with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum.

Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species are uncertain. A 2013 survey of animal biodiversity published in the mega journal Zootaxa puts this figure at over 25,000. Estimates of the total number of extant species are subject to even greater variation. A widely referenced article published in 1993 estimated there may be over 1 million species of nematode. A subsequent publication challenged this claim, estimating the figure to be at least 40,000 species. Although the highest estimates (up to 100 million species) have since been deprecated, estimates supported by rarefaction curves, together with the use of DNA barcoding and the increasing acknowledgment of widespread cryptic species among nematodes, have placed the figure closer to 1 million species.

Nematodes have successfully adapted to nearly every ecosystem: from marine (salt) to fresh water, soils, from the polar regions to the tropics, as well as the highest to the lowest of elevations. They are ubiquitous in freshwater, marine, and terrestrial environments, where they often outnumber other animals in both individual and species counts, and are found in locations as diverse as mountains, deserts, and oceanic trenches. They are found in every part of the earth's lithosphere, even at great depths, 0.9–3.6 km (3,000–12,000 ft) below the surface of the Earth in gold mines in South Africa. They represent 90% of all animals on the ocean floor. In total, 4.4 × 10²⁰ nematodes inhabit the Earth's topsoil, or approximately 60 billion for each human, with the highest densities observed in tundra and boreal forests. Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on earth, their diversity of lifecycles, and their presence at various trophic levels point to an important role in many ecosystems. They have been shown to play crucial roles in polar ecosystems. The roughly 2,271 genera are placed in 256 families. The many parasitic forms include pathogens in most plants and animals. A third of the genera occur as parasites of vertebrates; about 35 nematode species occur in humans.

Nathan Cobb, a nematologist, described the ubiquity of nematodes on Earth thus:

In short, if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes. The location of towns would be decipherable since, for every massing of human beings, there would be a corresponding massing of certain nematodes. Trees would still stand in ghostly rows representing our streets and highways. The location of the various plants and animals would still be decipherable, and, had we sufficient knowledge, in many cases even their species could be determined by an examination of their erstwhile nematode parasites.^(p 472)