NAA - naphthaleneacetic acid (NAA) is a plant hormone that is often used during propagation by cuttings to encourage root growth.
naked bud - having no bud scale to cover and protect the bud for example Viburnums
narrowleaf evergreen - ornamental conifers with comparatively long, slender leaves that remain green throughout the year such as firs (Abies), junipers (Juniperus), spruces (Picea) and yews (Taxus). See broadleaf evergreen.
naturalistic garden or wild garden -  a garden developed with plantings that either add to an existing native site or completely create an area that is or appears to be populated by native species. Achieved in beds or gardens by use of plants with loose or broad growth habit or those which multiply by rhizomes. Naturalizing plants are usually the same as those used to add unity and continuity to a landscape garden.
naturalizing - applied to plantings where the species expand and multiply in the setting. For examples, daffodils (Narcissus) will often increase from a few bulbs to a large number covering a wide area in a natural setting.
 
necrosis - the death of cells, tissues, or whole plants. Dead parts or plants are said to be necrotic and will generally turn black and rot. See chlorosis.
nematode - very small (usually, but not always microscopic) roundworms, threadworms, or eelworms that may become pests of plants.

A common nematode is the root knot nematode. A less common type called the foliar nematode is found in hostas. They cause browning of tissue between the veins of hosta leaves late in the season.
nightshade family - plants of the plant family, Solanaceae, including eggplant, tomatoes, potatoes, peppers plus petunias, nicotiana and nolana.  Several weed species are also included, one of which (Atropa belladonna) is known as belladonna or deadly nightshade because its berries are poisonous.
nitrogen - an element represented by the letter N that is required for plant growth. With a few exceptions, plants use nitrogen as a compound called nitrate. It is part of the chlorophyll molecule and, when in deficiency, is one of the factors that cause a leaf to turn yellow.

In fertilizers, it is indicated by the first of the three numbers i.e. 10-15-20 has 10% nitrogen in the form of elemental nitrogen.
nitrate - with the chemical formula, NO3, this is the form of nitrogen which is absorbed by most plants.
 
node - the segment of a stem where one or more leaves or axillary buds are attached. See internode.
non-selective herbicide - a herbicide that will indiscriminately kill or injure all plants that come in contact with it. See selective pesticide.
nut - a dry, indehiscent, hard, one-seeded fruit.
nutrient availability - Due to the chemistry of the situation, nutrients in the soil are more or less available to a plant depending on the pH (acidity or alkalinity) of the soil. Generally, most landscape plants do best in a slightly acid soil with a pH of about 6.0 to 7.0. Certain plants such as rhododendrons and azaleas, boxwood, pin oak and others are "acid loving" and need a pH of around 5.0 to thrive.
 

 

Copyright © 2000 -