Leach Botanical Garden, Botanical garden in Southeast Portland, United States.

Leach Botanical Garden covers 16 acres in outer southeast Portland, near S.E. 122nd Avenue and Foster Road. Johnson Creek divides the property, and most of the land lies on an incline. Its collection holds over 2,000 hybrids, cultivars, and native and non-native plants, including alpines, medicinal herbs, rock garden plants, camellias, and more than 125 fern species; many plants are labeled.

The garden began in 1931 as the landscaped grounds of botanist Lilla Leach and pharmacist John Leach, originally called Sleepy Hollow. Their cottage-style manor house was built in 1936; before it was finished they summered in a stone cottage near Johnson Creek. The garden was acquired by the Portland Parks Bureau in 1972, and a 5-acre expansion begun in 2018 was completed in 2021, bringing the site to 16 acres.

The garden keeps the name Sleepy Hollow that the Leaches gave their 1931 hillside home, and many of the more than 2,000 plants are labeled for self-guided walks. Lilla Leach, honored with the Garden Club of America's Eloise Payne Luquer Medal in 1950, collected ferns and other plants here; five plant species of the Pacific Northwest were discovered by the couple.

The garden lies near S.E. 122nd Avenue and Foster Road in outer southeast Portland. Johnson Creek divides the property, and most of the land is on an incline, so trails involve slopes. A self-guided tour follows the paths past labeled plants, firs, ferns and wildflowers.

Lilla Leach received the first Eloise Payne Luquer Medal from the Garden Club of America in 1950 for distinguished achievement in botany, and from 1945 to 1948 she directed Save the Myrtle Wood, Inc. The Leaches' will left the garden to the City of Portland on condition that the city assume maintenance within ten years, or the land would pass to the YMCA.