Staghorn fern

Identification and origin

Platycerium bifurcatum belongs to the Polypodiaceae family. Its native range extends from Java to New Caledonia and includes Queensland, New South Wales and Norfolk Island. In humid forests, this fern grows as an epiphyte on trunks and branches. It uses a tree for support without drawing sap from it, so it is not a parasite. It is the most frequently cultivated species in its genus, partly because it is easier to grow than several other staghorn ferns.

The plant makes two strikingly different types of foliage. Sterile basal fronds begin green, fleshy and rounded to heart-shaped. They press against the support, protecting the rhizome and roots, then become papery and tan to cinnamon brown as they age. They also catch organic debris that gradually supplies nutrients. Fertile fronds are gray-green, arching and repeatedly forked near their ends, producing the familiar antler outline. Their fine whitish fuzz slows water loss. Regular brown patches beneath the tips are spore-producing sori, not a disease.

A mature specimen becomes a crowded colony of offsets and generally reaches 2–3 ft in favorable cultivated conditions. Individual fertile fronds may be about 18 in long. The short rhizome spreads slowly over its support and produces fresh basal shields that eventually conceal the fasteners.

Light

Provide bright indirect light or bright, dappled shade. Near a window, a sheer curtain protects the fronds from intense midday sun; outdoors in summer, put the plant beneath a tree or a bright overhang. It can tolerate more direct sun when humidity and temperatures are high and water is readily available, but it still needs gradual acclimation. Dim light slows growth and produces weaker fronds. Avoid crowding it into a dark corner as well: air moving freely around the foliage helps discourage rot.

Watering

Water according to what you observe rather than on a fixed schedule. When the surface of the sphagnum or growing mix has dried slightly and the mount feels lighter, thoroughly soak both the root pad and the basal fronds, then let all excess water drain. For a mounted plant, temporarily immersing the pad can rehydrate it evenly; hang it up afterward so it drains freely. Roots should never remain waterlogged because this fern rots readily, but complete, extended dryness stresses young fronds.

Water demand rises with warmth, light and active summer growth, then falls in cooler weather when growth slows. Rainwater is a good choice when available. Moderate air humidity is beneficial; in a dry room, mist around the plant while maintaining air circulation. The fronds absorb some water too, but a light spray does not replace a thorough soaking of the root pad.

Potting mix

Mounted culture most closely matches the fern’s natural habit. Secure a young plant to a wooden board, bark slab or open wire basket over a small pad of sphagnum or coarse peat. Use fastening material that will not cut the plant, passing it over older brown basal fronds and never over tender green growth. Once established, new shields grow over and hide the fastening material.

A small specimen can also grow in a pot filled with a rich, coarse and exceptionally free-draining medium, such as an epiphytic orchid mix. Equal parts coarse leaf mold, loam and charcoal are another suitable combination. During active growth, apply a balanced diluted liquid fertilizer monthly, or place a small amount of slow-release fertilizer in the pad. Stop or greatly reduce feeding when growth slows.

Temperature

Normal household temperatures suit this fern, ideally between 55–81 °F. Keep it above 39 °F throughout the year, and bring a summering plant indoors before nights consistently approach that limit. It may survive a brief spell close to freezing, but this is not a desirable growing condition. It stays outdoors year-round only in very mild climates, USDA zones 9a through 13b. Keep it away from heaters, air-conditioning vents and cold air currents, all of which can dry or chill the fronds abruptly.

Repotting

A mounted plant is not repotted in the usual sense. When the colony has spread well beyond its base, the board deteriorates or the pad no longer holds enough moisture, transfer the entire plant to a larger support. Preserve as many protective basal fronds and attached roots as possible. For a potted specimen, act in spring only when roots become crowded, choosing a container just one size larger with generous drainage holes. Excess mix stays wet too long. Handle the plant gently, and never wipe away the gray coating on its fertile fronds.

Pruning

Do not remove a basal frond merely because it turns brown. This is a normal transition, and the dead shield keeps anchoring and protecting the colony until it falls away naturally. Do not rub the pale powdery covering from fertile fronds either. With a clean tool, cut only fertile fronds that are completely withered or broken, working near their bases without injuring the rhizome. No shaping is required.

Propagation

Dividing offsets is the most practical method. In spring or during a warm period of active growth, select a pup that has roots along with both basal and fertile fronds. Separate it with a clean, sharp knife and fasten it over a small moist pad. Keep the division warm, in filtered light and consistently moist until established, which may take considerable time. Growing from spores is possible, but it involves a tiny intermediate life stage and requires far more time and control, so it is rarely attempted at home.

Common problems

One symptom can have several causes. Check light, humidity, watering, temperature and air movement before taking action.

• Brown, dry basal shields: normal aging when they remain firm and attached to the support; leave them in place.
• Soft or black base with an unpleasant smell: a constantly saturated pad, poor drainage or stagnant air; allow more drying and improve drainage.
• Wilted fertile fronds: prolonged lack of water, dry heat or damaged roots; rehydrate the pad without leaving it soaked.
• Pale marks or scorched areas: too much direct sun too quickly, especially behind glass.
• Weak growth: insufficient light, cool conditions or too little nutrition during active growth.
• Even whitish coating on fronds: normal protective fuzz that should not be rubbed off.
• Cottony clumps or fixed shells: mealybugs or scale insects; isolate the fern and inspect folds carefully.
• Fine stippling and webbing: spider mites favored by very dry air.
• Black spots: prolonged excess humidity combined with poor air circulation.

Toxicity

No toxicity is reported for dogs, cats or horses. Still, keep wire, fishing line and other mounting materials away from animals that may chew them.