Ever­greens might also shed nee­dles this sea­son

Daily Southtown - - Homes - By Beth Botts

It’s nor­mal for de­cid­u­ous trees and shrubs to drop their leaves in au­tumn. Many home­own­ers don’t re­al­ize that it’s also nor­mal for ever­greens, such as pines, to drop some nee­dles.

“Nee­dles don’t last for­ever,” said Sharon Yiesla, plant knowl­edge spe­cial­ist at TheMor­ton Ar­bore­tum in Lisle.

“They live for a few years, and then they fall off.”

Shed­ding their old­est nee­dles ev­ery fall is a reg­u­lar part of the life cy­cle of evergreen trees and shrubs. New nee­dles — which are ac­tu­ally a kind of leaf— will growin spring.

“Most home­own­ers don’t no­tice as long as the tree sheds its old nee­dles grad­u­ally,” Yiesla said. “But they some­times be­come con­cerned if it seems to lose a lot of nee­dles at once.”

The nee­dle loss is of­ten most con­spic­u­ous on pines be­cause of their open branch­ing habit, and be­cause pine nee­dles grow— and fall— in bun­dles of two or more. That makes the loss more ob­vi­ous.

Spruces and firs dis­card nee­dles, too, but the loss is less ap­par­ent be­cause of their dense branch­ing and tight, pyra­mi­dal form. They also shed nee­dles singly in the in­te­rior of the tree where it’s hard to see.

The life span of an evergreen nee­dle de­pends on the tree species. White pine (Pi­nus strobus) has bun­dles of five long, slen­der nee­dles that last for two or three years be­fore they turn yel­low, then brown, and drop to the ground.

Aus­trian pine (Pi­nus ni­gra) and Scots pine (Pi­nus sylvestris) usu­ally dis­card their nee­dles af­ter three years, and red

pine (Pi­nus resinosa) af­ter four.

Some nee­dles are dis­carded ev­ery year, but a tree may some­times lose more nee­dles in dry years, when it is stressed by drought. A large fall of old nee­dles this au­tumn may also mean there­was an es­pe­cially large crop of new nee­dles a few years ago

Yew(Taxus) nee­dles turn yel­lowand drop in late spring or early sum­mer of their third year. Ar­borvi­tae (Thuja) sheds small fan-shaped branch­lets, rather than in­di­vid­ual nee­dles.

“As long as your tree is only los­ing older nee­dles, it’s nor­mal,” Yiesla said.

On any branch, the nee­dles or branch­lets clos­est to the trunk are the old­est. Nee­dle brown­ing is only a sign of trou­ble if it’s hap­pen­ing any­where else.

“If nee­dles are turn­ing brown and drop­ping all over the plant, it­may be stressed by drought, which is caus­ing the nee­dles to dry out,” Yiesla said. “That of­ten hap­pens on newly planted ever­greens that haven’t been wa­tered of­ten enough.”

When an en­tire pine tree turns brown, it may be a sign of dis­ease, such as pine wilt. Nee­dles that turn brown in patches along a pine tree’s branches may be a sign of cer­tain fun­gus dis­eases;

Aus­trian pine and Scots pine are es­pe­cially sus­cep­ti­ble. Cer­tain fun­gal dis­eases can also cause a spruce to lose nee­dles fromthe bot­tom up.

A sin­gle brown branch or a large brown patch on any evergreen may in­di­cate win­ter dam­age or an in­sect in­fes­ta­tion.

“Be­cause brown nee­dles can. be a symp­tom of so many dif­fer­ent things, you should al­ways seek ex­pert help to get a firm di­ag­no­sis be­fore you at­tempt any treat­ment,” Yiesla said. The Ar­bore­tum’s Plant Clinic can help find the source of the prob­lem.

Most of­ten, how­ever, there is no prob­lem. “As long as your tree is just los­ing older nee­dles in the mid­dle on a reg­u­lar ba­sis, it’s go­ing through its nor­mal pat­tern of growth and re­newal,” she said. “There’s no rea­son to be con­cerned.”

The nee­dles that fall to the ground will do what they’ve al­ways done— cre­ate a layer of nour­ish­ing, in­su­lat­ing nee­dles over the tree’s roots, like the floor of a piney­woods.

For tree and plant ad­vice, con­tact the Plant Clinic at TheMor­tonAr­bore­tum (mor­tonarb.org/plan­tad vice or plant­clinic@mor tonarb.org). Beth Botts is a staff writer at theAr­bore­tum.

MOR­TON AR­BORE­TUM

Ever­greens, in­clud­ing pines, dis­card their old­est nee­dles ev­ery year as part of their nor­mal cy­cle of growth.

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