Enchanted Garden at Howard County Library

The Enchanted Garden located on the premise of a new Howard County public library completed in 2011, was  developed on a site which was originally intended to be open space. The library brought 5 design/ build companies to the table and hosted a competition to determine who would design and build the children’s garden they desired. The design process took into consideration storm water runoff, the use of environmentally sensitive materials, educational elements, and useable space for large groups.

The landscape contractor was awarded the project because of their comprehensive design and playful details which exceeded the library’s expectations. The design incorporated two circular gathering areas for groups of children, furnished with custom chairs cut from large diameter logs. A pond and stream, permeable paver patio, cedar pergola, decomposed granite pathways, native plant pallet and raised planter beds all helped to make the space interactive and inviting to both children and adults.

The surrounding  garden has a stone veneer wall and metal fence to provide security. After one has passed through the curved iron gate, visitors are presented with the option to enter the permeable paver patio, partially covered by a custom built Western Red Cedar pergola, or can follow the decomposed granite path which winds through perennial gardens. Along the interior of the walls, decorative tiles were installed, each stamped with the hand print of a child who visited the library and participated in the commemoration of the garden. The pathways continue through gardens planted with various ferns, Juncus, Phlox, Amelanchier, and other native plants.

Located throughout the planting areas are drain inlets which flow into a storm sewer system installed by the landscape contractor. This system allows the site to drain runoff from any location with minimal sheeting across planting beds and pathways, preventing erosion and organic matter from flowing into the storm system , which leads to the public storm sewer.

A pond and stream dissect the northern half of the site, providing a teaching tool for lessons on aquatic ecosystems. The stream is lined with large boulders providing seating for visitors. Adjacent to the stream is a custom built steel arbor, planted with climbing roses. The arbor is constructed using curved galvanized tubing for the hoops, and is strung with stainless steel aircraft cable, utilizing hidden turnbuckles for tension adjustment. Adjacent to the pond and stream is the demonstration garden, built using 6×6 cedar timbers to form raised planter boxes and a matching potting bench. Double gates were installed at the north end of the garden to allow easy access for vehicles.

Ornamental trees are lit, as is the pergola, to provide night interest during events. The garden serves not only as a teaching resource with ornamental plaques labeling plants and highlighting the local ecosystem, but also as a center piece for the new library which opened in late 2011.

Special or Unusual Problems

The existing site plans were used as a base for the drawings which would become the Enchanted Garden, but grading and drainage modifications were necessary to ensure that all water would be adequately drained into the storm sewer system. The contractor worked with the project Civil Engineer to develop a drain system which was large enough to handle the flow for a 100 year storm. This required the installation of nearly 300 feet of 12″ diameter drain pipe, connecting to 9 drain inlets located across the surface of the garden. This drain system was also designed to handle water infiltration from the garden’s 1,000 square feet of permeable paver patio. The drain inlets were disguised by incorporating them into planting beds surrounded by a variety of water loving plants.

The landscape contractor was hired directly by the library, but because the entire building was still under construction, the project was coordinated through the building’s general contractor. The site was rough graded before the garden project began, but all excavation and fine grading was left to the landscape contractor. Over 230 cubic yards of soil were excavated and removed from the site to transform the area into the Enchanted Garden.

All plant material for the project was sourced from nurseries within a 50 mile radius of the project site, at the request of the library. Certain perennials, which were unavailable, forced the library and landscape contractor to agree on substitutions in order to keep the planting phase of the project on schedule during the fall of 2011.

Installation of the decomposed granite pathways included a compacted sub base with a weed barrier cloth installed on top of the soil. The granite was installed in 2″ lifts to ensure compaction through the entire depth. Liquid binding agent was mixed with the granite using a concrete drum mixer to ensure an even blend throughout and prevent the material from washing away during rain storms. After mixing, the material was spread over the surface, raked to final grade and mechanically compacted. This was done to cover the 2,600 square foot area, ensuring a consistent decomposed granite surface throughout the garden.

Spanning the stream is a 9 foot long, 3 foot wide and 12″ thick bluestone slab bridge. The stone was set in place before any of the pathways were installed, but after the stream was completed, to ensure the stone extended beyond each side of the rubber liner. Weighing nearly 2 tons, the stone was set in place using an excavator and final adjustments were made by hand to ensure the perfect fit. This bridge has become one of the highlights of the garden, allowing children to watch the water disappear beneath their feet.