While most folks are comfortable with deciduous trees losing their leaves in the fall, there is concern among gardeners when conifer needles begin yellowing, browning and dropping from the tree. Although evergreens stay green all year long, it doesn’t mean that individual needles live forever. In fact, it’s normal for some of the needles on evergreens to turn yellow or brown and fall from the tree this time of year. The seasonal needle loss is a natural occurrence.
Seasonal needle loss is, perhaps, most conspicuous on our native Western red cedar when the older foliage turns brownish red in color. The phenomenon, commonly referred to as cedar flagging, is most frequently the result of moisture stress. Summers of prolonged, dry weather will cause more flagging than moist, overcast summers. Previous-year weather stresses — from cold winters, or dry springs, summers or falls — may have already damaged the tree and could result in flagging during a summer or fall which is not particularly dry. Unless weather or cultural stress are severe, trees with cedar flagging should recover. Fall and winter winds blow most of the dead foliage out of the trees before spring.
Interestingly, trees growing near lakes or other bodies of fresh water may also develop flagging during dry summer weather, even though they are near a source of water. Such trees have shallow root systems, dependent on high water tables in these locations. When droughts occur, the water table drops, leaving the root system without adequate moisture.
Evergreen needles have varying life spans, depending on the species. Arborvitae and pine needles live for two years, while spruce needles live for three years or longer. Some species of evergreens have a more noticeable leaf drop than others. In the fall, arborvitae and white pine often drop their 2-year-old needles all at once which can be quite alarming if you don’t realize it is perfectly normal.
Environmental stress such as drought and hot temperatures may cause greater than normal loss of needles. The normal pattern of seasonal needle loss is a gradual discoloration and eventual loss of inner needles from the top to the bottom of the trees. In contrast, fungal diseases often cause browning of the newest (outermost) needles, death of the entire branches or thinning of needles on just the lower branches.
On other species, needle drop occurs gradually, with a small number of needles falling at one time. Foliage developed during the current year (at the branch tips) remains green. The older needles of yew for example, will turn yellow and drop in late spring or early summer. Broad-leaved evergreens, such as rhododendrons, drop their 2- to 3-year-old leaves in late summer and early fall.
Inner and lower needles that are hidden from light are usually the first to drop. Pruning excess growth and dead limbs can help open the plant to more light.
Extend squash shelf-life
with proper storage
With the arrival of several light frosts earlier this month, many home gardeners are wondering when they should harvest their squash and pumpkins. Although these two vegetables can tolerate a light frost that kills the vines, a hard freeze with temperatures of less than 27 degrees F. can do severe damage. While the majority of pumpkins never make it past Halloween, most gardeners strive to store squash into the winter months. Storing squash for an extended period is not that difficult, provided you pick them at the right time and store them properly.
Pick the squash from the vine when it is mature, leaving about one inch of the stem intact. Winter varieties such as table queen, Hubbard and Turbans develop a hard shell. Marblehead and golden delicious, whose skins remain tender, are exceptions. The fact that the shell of winter varieties that are allowed to become mature cannot be penetrated with the thumbnail is not necessarily assurance that the squash is ripe, although it is an indication that maturity is being approached.
It’s also important to observe the outer appearance. Mature fruit has a dull and dry skin compared to shiny, smooth skin of immature fruits. If you’re still not sure, check the ground color or that area of the squash that has contact with the soil. When mature, the ground color changes from white to a cream or gold color. The seed fibers of a mature squash are stringy. The seeds should stand out by themselves and are no longer encased in tissue, like peanuts in a piece of peanut brittle.
Remember to cut, rather than breaking off the stems of Hubbards and other fleshy-stemmed squash, leaving about two inches of stem.
This column is printed as a service of the Washington State University Extension Office at Elma. Donald D. Tapio is the regional gardening and farming specialist for Grays Harbor and Pacific counties. He can be reached at (360) 482-2934 or firstname.lastname@example.org.