A parterre is a formal garden construction on a level surface consisting of planting beds, edged in stone or tightly clipped hedging, and gravel paths arranged to form a pleasing, usually symmetrical pattern. It is not necessary for a parterre to have any flowers at all. French parterres originated in 15th-century Gardens of the French Renaissance. The castle parterre is a simple symmetrical design of four squares, divided into four triangular herb beds. The centre point of the squares feature a clipped yew tree while the centre point of each herb bed features a shaped laurel bay tree.
One of the most important household duties of a medieval lady was the provisioning and harvesting of herbs and medicinal plants and roots. Plants cultivated in the summer months had to be harvested and stored for the winter. Although grain and vegetables were grown in the castle or village fields, the lady of the house had a direct role in the growth and harvest of household herbs.
Herbs and plants grown in manor and castle gardens basically fell into one of three categories: culinary, medicinal, or household use. Some herbs fell into multiple categories and some were grown for ornamental use.
The Allee at Drimnagh castle features hornbeam trees, their function was to provide shade for the land owners, the belief being “the paler one was, the more noble one was deemed”.
The common English "hornbeam tree" derives its name from the hardness of the wood, and was often used for carving boards, tool handles, shoe lasts, coach wheels, and for other uses where a very tough, hard wood is required. The plant beds either side of the trees, feature snowdrops, bluebells, tulips, daffodils, some ferns and hellebores.
Hornbeam leaves are popular for their use in external compresses to stop bleeding. Their haemostatic properties also help in the quick healing of wounds, cuts, bruises, burns and other minor injuries. A yellow dye is obtained from the bark.