Yes—there are outdoor benches designed specifically for this problem, but they are not always labeled as “extra-long armrest benches” in big-box stores. What you want is often called an assisted-standing bench, senior outdoor bench, ADA bench with armrests, or heavy-duty park bench with full-length armrests.
For an elderly mother who has trouble standing up, the most important feature is armrest geometry. Look for armrests that extend all the way to the front edge of the seat, or even slightly beyond it. This lets her place her hand directly beside or slightly in front of her hip and push straight down, which is much easier than reaching backward. Standard park bench armrests stop too early, so she has to twist and pull, which can feel unstable and require more strength.
Seat height matters just as much. A seat height around 18 to 20 inches is usually better than a low 15 to 16 inch bench. If the seat is too low, even great armrests will not make standing easy. Also check the armrest height above the seat. Around 7 to 9 inches above the seat surface is comfortable for pushing up.
Sturdiness is non-negotiable. Choose a bench made from powder-coated steel, heavy-gauge aluminum, or commercial recycled plastic with a metal frame. It should feel heavy and should not tip or slide when she pushes down on one armrest. If possible, anchor it to a concrete pad or patio, or choose a bench with a wide, heavy base. Look for a weight capacity of at least 300 pounds, though 400 to 500 pounds is better for real confidence.
Some good search terms when shopping are “outdoor senior bench with assist arms,” “bariatric outdoor bench with armrests,” “commercial park bench with extended armrests,” and “assisted standing garden bench.” If you have a local site-furnishings dealer or a medical supply store that carries outdoor seating, ask for a seated-to-standing outdoor bench with long grab arms.
A specific style that often works is a bench with a transfer arm or grab bar built into the front of the armrest, similar to an indoor transfer chair but weatherproofed for outdoor use. These are common in senior living communities, memory care gardens, and physical therapy outdoor spaces. You may also consider a wider bench with armrests on both sides and a center armrest for extra push points.
If you cannot find one with armrests long enough, a simple alternative is to pair a well-built bench with an outdoor-rated grab bar or a sturdy, weighted patio railing installed at the correct height beside it. But for most families, a heavy-duty bench with full-length armrests, an 18 to 20 inch seat height, and a non-slip surface is the most practical answer.
Before buying, try to test it in person. Have your mother sit and stand while pushing on the armrests. Watch that the bench does not slide, tip, or rock. If the armrests feel too short or too low, keep looking. The right bench can give her a safer, more enjoyable way to spend time outdoors.