What can visitors see and do in fall?

Leaf Peeping

The U.S. Capitol Grounds are a showcase for the many hues of fall, given the number and diversity of large and historic trees comprising the arboretum. The top 10 tree species to seek out for fall color enjoyment are: Bald Cypress, Sugar Maple, Red Maple, Ginkgo, Sweetgum, Sassafras, Sourwood, Black tupelo, Flowering dogwood and Japanese maple.

Fall foliage in Washington D.C.'s Bartholdi Park.
Height of the autumn season on the U.S. Capitol campus.
Fall foliage seen on the U.S. Capitol's East Front Plaza.

Why do leaves change colors?

Deciduous trees spend all spring and summer making their own food from sunlight, carbon dioxide and water — a process known as photosynthesis. Leaves are food production factories for trees which have numerous cells containing a pigment knows as chlorophyll, which gives leaves their green color. As winter approaches, days get shorter and deciduous trees are gearing up for the cold months ahead by slowing photosynthesis. As this happens, bright green chlorophyll breaks down revealing other pigments that give way to new colors such as the red (anthocyanin) found in many oaks, the oranges (carotene) seen in sugar maples and the yellow (xanthophyll) of ginkgo trees.


View of the U.S. Capitol from under a gingko tree on the West Front.
View of the Supreme Court Building from under a gingko tree on the U.S. Capitol's West Front.
View of fall foliage from the Garfield Monument just west of the U.S. Capitol.

Capturing resplendent fall colors on camera can help turn a visit to the U.S. Capitol into a lasting memory. The beautiful vistas and garden vignettes originally designed by Frederick Law Olmsted make it easy for photographers — amateurs as well as professionals — to compose and shoot awe-inspiring images.

We have some practical, insider tips on how to take the best shots in fall, and please note: tripods are not allowed on the U.S. Capitol Grounds without obtaining a special permit from the United States Capitol Police.

What does the AOC work on in fall?

Fall is one of the busiest seasons for Capitol Grounds and Arboretum staff at the AOC. Preparing for both winter and spring requires significant advance planning and effort throughout the fall.

Leaf Removal

The AOC Capitol Grounds and Arboretum crew clears autumn leaves.
The AOC Capitol Grounds and Arboretum crew clears autumn leaves.

The Capitol Grounds and Arboretum Maintenance Division clears thousands of cubic yards of leaves from the U.S. Capitol Grounds, which are later composted for future fertilization. It also hauls in new materials such as mulch to help gardeners prepare flower beds and turf lawns for winter weather.

Planting, Tilling and Turf Work

AOC Capitol Grounds and Arboretum preparing plant beds for spring during the autumn season.
AOC Capitol Grounds and Arboretum planting bulbs during the autumn season.

Capitol Grounds gardeners pull, till and amend more than 160 flower beds. They plant approximately 110,000 springtime bulbs, including Asiatic Lilly, Crocus, Dutch Iris, Fritillaria, Hyacinth, Muscari, Tulips and around 5,000 assorted Pansies. Grounds crews also aerate, seed, sod, mulch and organically fertilize turf lawns. Meanwhile, gardeners choose the annual color palette for the following year's flowers as well as the selection of summer annuals.

Water Feature Maintenance

View of fall foliage at the Grant Memorial and Capitol Reflecting Pool.

The six-acre Capitol Reflecting Pool undergoes major maintenance in the fall. AOC workers use heavy equipment to drain and clean the pool, removing the sludge that collects throughout the year. In addition, irrigation systems are flushed and winterized, and catch basins are repeatedly cleaned to ensure proper drainage.

Winter Weather Preparation

Long before frigid temperatures bring winter snow and ice to the Capitol campus, grounds crew preparations shift into high gear: 500 tons of rock salt for road surfaces and 20 tons of deicer for sidewalks and steps are purchased; snow removal equipment is repaired; winter fuel supply is prepared and coordinated; and safety training on snow removal processes and equipment is conducted.

Tree Care

Trees are a major feature of the U.S. Capitol Grounds and continue to reflect Frederick Law Olmsted's original landscape design, a vision which drives all landscaping decisions on the grounds today. As "living witnesses to history," many of the trees on the grounds are gifted, memorial or commemorative trees that bear special plaques identifying their species and their historic significance.

The AOC's arborists prune trees throughout the year for their health as well as for the safety of people and property below. New trees are also planted and prepared for winter, allowing time for the trees to build root mass before they become dormant in colder temperatures.

AOC staff identify vacant planting sites and research tree species that are thought to have once existed in a specific site according to the Olmsted plan, but have since been removed. If appropriate, new trees are planted if they help to incrementally bring the Capitol Square landscape back to the Olmsted 1874 plan.

Many tree species that may have been present in the historic landscape are no longer considered appropriate due to environmental changes and the emergence of exotic invasive species. In such cases, alternatives are selected that reflect the similar texture or habit of Olmsted's plan.

About the U.S. Capitol Grounds

The U.S. Capitol Grounds are comprised of approximately 286 acres, including the U.S. Capitol, Senate and House office buildings, the Capitol Power Plant and Union Square. The Capitol Grounds and Arboretum jurisdiction of the AOC is responsible for both the day-to-day maintenance of the U.S. Capitol Grounds and the preservation of a significant historic landscape and accredited arboretum originally designed by Frederick Law Olmsted. In addition, every aspect of caring for the Capitol campus follows rigorous environmentally sustainable practices.

For an easy and on-the-go reference to all that the U.S. Capitol Grounds have to offer, download the Capitol Grounds app to your phone. Explore the interactive map, photos, audio clips, historic details and more. Visit the Apple Store or Google Play to download the app today!