Well-meaning folks who live near park property and think that transplanting garden cuttings or composting yard clippings there would be helpful, actually may do harm. Loose seeds and trimmings from such yard waste frequently take root, multiply, and overwhelm native plants. Trees heavily matted with bittersweet vines are very susceptible to wind and ice damage. It thrives on the fringes of disturbed natural areas like the long boundary of Rock Creek Park in Washington, D.C., outcompeting native species for water and nutrients. Its berries, which resemble porcelain beads and thus make it popular with landscapers, change color from white to a series of pastel shades of yellow, lilac, and green before finally turning blue and purple.
Most varieties have white flowers, although some boast pink or crimson blooms and even fragrance.
Bush honeysuckles can quickly invade and overtake an area, creating dense stands that threaten native plants by decreasing available light and depleting soil moisture and nutrients. Nicknamed the Purple Plague, purple loosestrife is a particular problem at Kenilworth Aquatic Gardens in Washington, D.C., the only national park devoted to water plants.