Monkey Grass is a widely used term in landscaping, referencing a group of evergreen, grass-like groundcover plants chosen for their hardiness and texture. These plants offer a low-maintenance solution for borders, mass plantings, and areas where traditional turf grass struggles to grow. The mature height of Monkey Grass directly determines its suitability for various roles, such as short edging or dense groundcover, making knowledge of the specific variety’s potential height necessary for garden design.
Identifying the Different Types of Monkey Grass
The common name “Monkey Grass” refers to two distinct plant genera that differ significantly in growth habits and ultimate size: Liriope (Lilyturf) and Ophiopogon (Mondo Grass). Both share the characteristic of having long, narrow, evergreen foliage, but they occupy different height ranges in the garden.
Liriope varieties generally grow taller, possess wider leaves, and produce prominent flower spikes that rise above the foliage in summer. These plants typically form dense, clump-like mounds, though some species have a more aggressive spreading habit. Ophiopogon species, by contrast, are usually shorter and more compact, with thinner leaves. Their flowers are often inconspicuous, tucked down within the leaves, and they tend to spread slowly, forming a dense, carpet-like groundcover.
Specific Height Ranges by Variety
The maximum height of Monkey Grass depends heavily on the specific variety chosen, with a range that spans from a few inches to two feet tall. The taller varieties generally belong to the Liriope genus. For example, Liriope muscari, a common clumping variety, typically reaches a mature height between 12 and 18 inches. Cultivars such as ‘Big Blue’ or ‘Super Blue’ can grow even taller, sometimes reaching up to 24 inches under ideal conditions.
The shorter varieties are primarily found within the Ophiopogon genus. The standard Ophiopogon japonicus, or Mondo Grass, usually matures at a height between 6 and 12 inches. For the shortest groundcover needs, Dwarf Mondo Grass (Ophiopogon japonicus ‘Nana’) is a popular choice, topping out at 2 to 4 inches. Black Mondo Grass (Ophiopogon planiscapus ‘Nigrescens’) is an intermediate variety, usually growing to about 8 inches tall.
Factors Influencing Final Height
While genetics determine the maximum potential height of any Monkey Grass variety, environmental conditions decide how closely the plant will reach that potential. Soil quality and water availability are significant factors in vertical growth. Plants established in rich, well-draining soil with consistent moisture tend to achieve greater height and density compared to those in poor or dry soil.
Sunlight exposure also influences the final height and appearance of the foliage. Both Liriope and Ophiopogon tolerate a wide range of light, but deep shade can cause the leaves to become “leggy,” stretching vertically in an attempt to find light. Conversely, intense heat and drought stress will often suppress growth, causing the plant to remain shorter than its genetic maximum. The use of a slow-release fertilizer in early spring can encourage healthy growth, but excessive fertilization may lead to weak, overly tall foliage that flops over.
Maintaining Desired Height and Appearance
Managing the height and aesthetic appeal of Monkey Grass, particularly the taller Liriope varieties, often involves seasonal pruning. The most effective method is to cut back the foliage annually in late winter or very early spring, before the new season’s growth begins. Trimming the old leaves down to about three inches high removes winter-damaged foliage and makes way for fresh, green blades.
For large areas, a lawnmower set to its highest setting can be used for a quick and uniform trim, taking care not to injure the plant’s crown. This yearly cut does not permanently reduce the plant’s mature height, but it ensures that the new growth is dense and uniform throughout the growing season. Cutting back the old foliage also helps to improve air circulation and limits the potential for fungal issues.