See thousands of orchid plants in bloom (October is peak season), get expert advice, listen to lectures and peruse a sales tent full of quality plants and supplies at the National Arboretum’s Annual Orchid Show and Sale from 9 a.m. to 5 p.m. Sunday. Next Saturday, the arboretum will sell most of its popular koi from 9 a.m. to 2 p.m., with a preview starting at 8 a.m. The colorful fish, which range from $1 to $150, depending on size and quality, must be sold because their pool is being drained for renovations. All sales are final. 3501 New York Ave. NE. 202-245-2726. www.usna.usda.gov
Through Monday, during Potomac Mills’s Fall Super Sale Weekend, save more on already-discounted apparel, accessories, home goods and electronics at more than 200 off-price stores, including Last Call by Neiman Marcus, where you can take an additional 30 percent off your entire purchase. 10 a.m.-9 p.m. Monday-Saturday, 11 a.m.-6 p.m. Sunday. 2700 Potomac Mills Cir., Woodbridge. 703-496-9330. www.potomacmills. com.
Reddz Trading, a two-year-old secondhand clothing boutique, carries limited-edition Louis Vuitton handbags, vintage Chanel jackets and one-of-a-kind David Yurman necklaces. Among the current stock is a green Chanel coat for $500, originally $3,400. After items have been discounted three times, they go to Reddz’s Penny Rack, where everything really costs only a penny. 11 a.m.-8 p.m. Monday-Saturday, noon-6 p.m. Sunday. 7801 Woodmont Ave., Bethesda. 301-656-7333. www.reddztrading.com.