Festuca

Blue fescue (Festuca glauca) is a small, neat, evergreen ornamental grass native to Europe, grown almost entirely for its striking foliage: it forms a tidy, rounded, hedgehog-like tuft of fine, needle-thin, intensely steel-blue leaves. In early summer slim, wheat-coloured flower spikes rise just above the dome and fade to buff. Compact and orderly, it reads as a cool blue mound that holds its shape and colour through the seasons. Honesty matters with this grass: the famous blue is at its brightest only in full sun and lean, sharply drained soil - in rich, wet, or shaded ground it sulks, greens out, and rots. It is also short-lived, tending to die out in the centre after three or four years, so it must be lifted and divided regularly to keep fresh blue tufts coming. Like most exotic ornamental grasses it offers little to wildlife compared with native bunchgrasses. The trade's best-known form is the cultivar 'Elijah Blue', which holds the RHS Award of Garden Merit.

Idaho fescue is the plant that the small blue mound in every garden centre is imitating. That mound is almost always Festuca glauca, a European ornamental that dies out in the centre and wants replacing every few years; Idaho fescue is the western North American original, a densely clumping, long-lived perennial bunchgrass with the same fine blue to grey-green foliage on a plant roughly three times the size and with a genuine ecological job. It is a cool-season grass, flowering April to July on stiff stalks that stand about twice the height of the leaf tuft, and it is built underground rather than sideways: thick, deeply penetrating roots carrying symbiotic mycorrhizae, and no rhizomes at all. That is the whole difference between this grass and red fescue, the creeping lawn species in this same group. Idaho fescue never knits into turf, never repairs a gap by running, and cannot be mown as a lawn. What it does instead is hold a slope. The Lady Bird Johnson Wildflower Center calls it drought tolerant and excellent for erosion control, and notes the trap in the same breath: seedlings are only weakly competitive, and only mature plants become strongly competitive. Add that its seed is commercially available but not highly germinable, and the honest summary of establishment is that this is a two-to-three-year project on a weedy site, not a one-season fix. Two more caveats belong up front. There is no Missouri Botanical Garden PlantFinder profile for this species and no RHS Find a Plant entry, so this record rests on a native-plant database and an encyclopedia rather than on horticultural trial guidance, and it is thinner on garden performance than the fescue records around it. And its documented ground is western: rocky slopes and dry openings in woods, from British Columbia and Alberta south through the mountains to central California and Colorado. Nothing cited here describes how it behaves in a humid eastern summer, so this record does not guess.

Red fescue is the fescue in this catalog that is a lawn before it is an ornament. It is a low, fine-leaved, slowly spreading perennial grass with a circumboreal native range covering most of Europe, Siberia, China, Japan, Korea and most of the United States and Canada, and it is one of the most widely sown turf and revegetation grasses in the world. Two facts about buying it matter more than anything in the description. First, almost nothing is sold as the plain species. Wikipedia records many subspecies and many cultivars bred for the horticulture trade, and the two a gardener actually meets behave differently: creeping red fescue, subsp. rubra, is the one the common name refers to, while Chewings fescue, subsp. commutata, is a bunch grass that does not run at all. Habit here is a subspecies property, not a species property, so a bag labelled red fescue does not by itself tell you whether the grass will knit. Second, the sources disagree about light, and the disagreement is informative rather than sloppy. The Royal Horticultural Society says to grow it in full sun, describing an ornamental clump for a gravel garden or a meadow. Wikipedia says it prefers shadier areas and is often planted for its shade tolerance, describing why it is in every shade lawn mix on the shelf. Both are accurate about the plant they are describing. What is not in dispute is the low-input case: the RHS flags it drought resistant, asks for poor to moderately fertile well-drained soil, and rates it generally pest-free and disease-free. The limits are just as plain. Chewings fescue is recorded as not particularly tolerant of heavy wear or of mowing closer than 0.2 inches, and red fescue has never been a forage grass because its productivity and palatability are low. Read it as the fescue for a lawn, a bank or an unmown carpet on poor soil. Sheep fescue (Festuca ovina) and Idaho fescue (Festuca idahoensis) in this same group are clumping grasses for ornament and restoration, and blue fescue (Festuca glauca) is a blue mound for a rockery. Only this one is turf.

Sheep fescue is the fescue that stays a tuft. Wikipedia states it in four words - it has no rhizomes - and that is the single most useful fact about the plant, because it is what separates it from red fescue (Festuca rubra), the creeping fescue of lawn seed and turf mixes. Sheep fescue does not knit into a sward. It builds a dense, discrete, greyish-green hedgehog of short bristle-like leaves and stays exactly where it was put, which makes it an ornamental and a restoration grass rather than a lawn grass, and which is the axis this catalogue asks readers to choose on. The Royal Horticultural Society describes it as a native British grass, common throughout the British Isles, an important component of acid grassland on heaths, moors and mountains, and important fodder for upland sheep, which is where the name comes from. It wants full sun and well-drained acid to neutral loam or sand, holds evergreen tussocks of tightly rolled leaves, and carries compact sprays of purple-tinged green flowers in late spring and early summer. Two warnings belong on the label before any of the good news. The first is that the label itself is unreliable. Wikipedia says outright that this species is sometimes confused with hard fescue (Festuca trachyphylla), the RHS carries separate entries for fine-leaved sheep's fescue (Festuca filiformis) and viviparous sheep's fescue (Festuca vivipara), and most of the blue-grey garden material in the trade is sold as Festuca ovina 'Glauca', which this catalogue records separately as Festuca glauca. A bag labelled sheep fescue can be several different plants, so buy a named selection when identity matters. The second is geography. This is a Eurasian grass. Kew records it as introduced in California, Oregon, Washington, Utah, Missouri, Illinois, Kentucky and most of New England, so a North American restoration planting that needs a native clumping fescue wants Idaho fescue (Festuca idahoensis) instead. Where sheep fescue genuinely earns its place is ground nothing else wants: it tolerates both basic and acid soils, colonises old mining sites and spoil heaps contaminated with heavy metals, and owes much of that tolerance to mycorrhizal fungi that extend its effective root reach. It is also a real larval host, which is the one thing the blue ornamental fescues cannot claim.