The invasion

Restor­ing roots: Friends of Poquess­ing mem­bers say vo­lun­teers are needed on April 27 to help re­move in­vas­ive spe­cies from along the Glen Fo­erd Es­tate creek banks, to re­store the view and bring back nat­ive plant life. Pic­tured, an os­prey builds its nest on

Had Charles Mac­alester happened upon the con­flu­ence of the Poquess­ing Creek and Delaware River today, he might’ve built a Ja­pan­ese yashiki there in­stead of a grand Vic­tori­an man­sion, such is the dom­in­ance of bam­boo on the present-day Glen Fo­erd Es­tate.

The tower­ing plants are nat­ive to the Far East, but have man­aged to in­vade and take over much of the city-owned park and his­tor­ic­al site, ob­scur­ing views of the creek and the river, while chok­ing out many of the nat­ive flora that likely in­flu­enced Mac­alester’s de­cision to build his home there some 160 years ago.

For­tu­nately for folks who now en­joy the man­sion and sur­round­ing acre­age due to the stew­ard­ship of the Glen Fo­erd Con­ser­va­tion Cor­por­a­tion, the bam­boo wasn’t there when Mac­alester showed up. So he built his man­sion in peri­od-ap­pro­pri­ate style. It was only later, ac­cord­ing to the es­tate’s ex­ec­ut­ive dir­ect­or, Meg Sharp Walton, that he or his suc­cessors in­tro­duced the re­si­li­ent, fast-grow­ing woody grass, among many oth­er non-nat­ive plants, to the site.

The fam­ily of Robert Fo­er­der­er oc­cu­pied the es­tate for most of the 20th cen­tury and, like many well-to-do clans of the time, planted many exot­ic for­eign spe­cies as a show of op­u­lence. Today, they are con­sidered a nuis­ance.

“Ever since we’ve been part­ner­ing with the Friends of Poquess­ing Wa­ter­shed, we’ve talked about how we could edu­cate people about the creek,” Sharp Walton said. “It’s really, really beau­ti­ful here, but be­cause of the in­vas­ives, you get no sense that Glen Fo­erd bor­ders on the creek.”

Now, the creek’s and the es­tate’s care­takers have be­gun the prodi­gious task of clear­ing the in­vas­ive plants and try­ing to re­vive the nat­ive ones. The Pennsylvania En­vir­on­ment­al Coun­cil also sup­ports the ef­fort.

Vo­lun­teers plan to re­move un­wanted plants and lit­ter from the creek bank on April 27. The pub­lic is in­vited to take part. In fact, a week­end of en­vir­on­ment­al pro­gram­ming will start on Fri­day, April 26, when Phil­adelphia wa­ter­way his­tor­i­an Adam Lev­ine will speak about the city’s wa­ter­sheds and sew­er sys­tem at 7 p.m. at Holy Fam­ily Uni­versity’s Edu­ca­tion and Tech­no­logy Cen­ter. Ad­mis­sion is free.

Glen Fo­erd will host a bird walk at 7 a.m. on Sat­urday. It’s free to mem­bers of the his­tor­ic­al site and costs $3 for non-mem­bers. The Poquess­ing clean-up event will start at 9 a.m. and is free.

“In a nut­shell, we want to re­place what shouldn’t be here with nat­ive plant­ings,” said Su­z­anne Zlot­nick, vice pres­id­ent of edu­ca­tion for the Friends of Poquess­ing. “We want to re­store the stream bank to the way it should be without spe­cies that don’t be­long in Pennsylvania. We want this to have nat­ive plant­ings as it should be his­tor­ic­ally and nat­ur­ally.”

Robin Eis­man, a Friends of Poquess­ing mem­ber and Ph.D. spe­cial­iz­ing in eco­lo­gic­al res­tor­a­tion, can name many of the non-nat­ive trees, shrubs, vines and grasses on sight. The prin­cess tree or paulownia is nat­ive to China and is banned in Con­necti­c­ut, but is sold openly on­line, she said. Wine­berry is also nat­ive to the Far East and banned in a couple of U.S. states. Oth­er non-nat­ive plants in­clude Eng­lish ivy, Nor­way maple and Ja­pan­ese hon­ey­suckle.

The jus­ti­fic­a­tion for re­mov­ing them is both visu­al and eco­lo­gic­al.

“En­vir­on­ment­ally, be­cause all of the [loc­al] wild­life has evolved with the nat­ive plants, these [in­vas­ive plants] have taken away food sources from the hab­it­at,” Eis­man said. “It af­fects the mam­mals, the birds, the am­phi­bi­ans and rep­tiles in this area in gen­er­al.”

Bam­boo is en­emy No. 1. What began per­haps as a single row of low, or­na­ment­al plants along the slop­ing banks of the river and its trib­u­tary is now a thick­et, some 10 feet deep and at least that tall. In ad­di­tion to ob­scur­ing many of the es­tate’s nat­ur­al vis­tas, it blocks walk­ways once used by the home’s af­flu­ent res­id­ents to stroll along the wa­ter.

“[Bam­boo] was very pop­u­lar with wealthy in­dus­tri­al­ists” in the early 20th cen­tury, Sharp Walton said. “[But] it has taken over and it will con­tin­ue to do so. We con­stantly have to clear it and it en­croaches onto the path­way.”

For birders, the bam­boo also ob­scures a rare fam­ily of os­preys that began nest­ing atop a river buoy more than a dec­ade ago and that re­turn each spring. Cindy Fer­guson, dir­ect­or of op­er­a­tions for the Pennsylvania En­vir­on­ment­al Coun­cil and a res­id­ent of nearby Salem Har­bor, says that an adult fe­male os­prey po­si­tioned her­self low in the nest about 10 days ago and may already be in­cub­at­ing a new set of eggs.

Iron­ic­ally, oth­er birds also are to blame for the spread of in­vas­ive plants, as is the life-giv­ing wa­ter that flows along­side the es­tate. Ac­cord­ing to Eis­man, birds and wa­ter carry seeds long dis­tances and can de­pos­it them where they were nev­er in­ten­ded to flour­ish.

For Sharp Walton, the pro­ject must meet the en­vir­on­ment­al needs of the site while stay­ing true to her or­gan­iz­a­tion’s his­tor­ic­al mis­sion.

“The caveat for Glen Fo­erd is pre­serving the his­tor­ic­al land­scape,” Sharp Walton said. “The Macalasters were big on trees and the Fo­er­der­ers were hor­ti­cul­tur­ists. [But] with the banks, the first is­sue is the eco­sys­tem.”

For in­form­a­tion about Glen Fo­erd on the Delaware, vis­it www.glen­ or call 215-632-5330. •• 

Re­port­er Wil­li­am Kenny can be reached at 215-354-3031 or

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