Hoya Undulata is a highly sought-after houseplant, known for its distinctive foliage and its often elusive, yet rewarding, bloom. Its unique blossoms transform it into a spectacular floral display.
Understanding Hoya Undulata
Hoya Undulata, first described in 2015, originates from the humid, tropical environments of Borneo, specifically the Kalimantan region of Indonesia. It thrives as an epiphyte, naturally growing on other plants like trees in moist, shaded forest conditions.
The plant’s name, ‘undulata,’ refers to its rigid, lance-shaped leaves, characterized by their wavy or undulate margins and unique crinkly appearance. Leaf coloration varies from olive green to deep burgundy, sometimes with pink variegation, depending on light exposure.
The Unique Hoya Undulata Bloom
The bloom of Hoya Undulata distinguishes it within the Hoya genus. Flowers are typically star-shaped with a waxy, porcelain-like texture, appearing in shades of pink, salmon, or peach with contrasting white centers. Their surface is fuzzy due to tiny hairs.
Individual flowers are small, 2 to 4 centimeters in circumference, and gathered in an umbel. A unique feature is its corona, with lobes developing two lateral hooked appendages. While some Hoyas have strong fragrances, Hoya Undulata flowers possess a sweet, subtle aroma. Blooms are short-lived, lasting three to five days.
Essential Care for Undulata Blooms
Providing the right environmental conditions encourages Hoya Undulata to bloom.
Light
Bright, indirect light is ideal for flower production. Place the plant near an east-facing window or a few feet back from a shaded south or west-facing window, providing 50-60% light intensity. Too much direct sunlight can scorch leaves, while insufficient light hinders blooming.
Watering
Hoya Undulata prefers its soil to dry out slightly between waterings. Overwatering leads to root rot and discourages flowering. During active growth (spring and summer), water every three to four days. Reduce frequency to about once every two weeks in cooler seasons. Thoroughly saturate the soil until water drains from the pot’s bottom.
Humidity and Temperature
High humidity levels, 65% or higher, benefit Hoya Undulata, reflecting its native tropical habitat. While it tolerates moderate humidity around 50%, higher levels are better. Warm temperatures are also important, as this plant thrives when temperatures are consistently above 75°F (24°C).
Fertilization
Fertilization supports the plant’s energy demands for producing flowers. During the active growing season (spring through summer), a balanced fertilizer or one with higher phosphorus content encourages bloom development. Apply fertilizer at half strength once a month. No fertilization is needed during winter dormancy.
Potting Medium and Size
The choice of potting medium and pot size influences blooming. Hoya Undulata requires a well-draining soil mixture rich in organic matter to prevent waterlogged roots. Recommended components include coconut husk, charcoal, volcanic rock, or pumice, which provide excellent aeration and drainage. Hoya Undulata blooms more readily when slightly root-bound, so select a snug pot.
Troubleshooting Bloom Issues
If a Hoya Undulata is not blooming despite consistent care, several factors may be at play.
Plant Immaturity
Many Hoyas require a certain age, often two to seven years, before flowering.
Insufficient Light
A lack of bright, indirect light prevents the plant from accumulating energy for flower production. Moving the plant to a brighter location, without harsh direct sun, can resolve this.
Watering and Potting Mix
Overwatering or a potting mix that retains too much moisture can inhibit blooms by stressing the root system. Ensure proper drainage and allow the soil to dry adequately between waterings.
Water Stress
A slight water stress can signal the plant to initiate blooming. Carefully withhold water until leaves show slight puckering or wrinkling before a thorough watering.
Pot Size
Ensure the plant is not in an overly large pot, as this can cause it to focus energy on root growth rather than flowering.
Post-Bloom Care
After Hoya Undulata finishes blooming, specific care ensures its continued health and encourages future flowers. Do not remove the spent flower stalk, known as a peduncle. New blooms emerge from the same peduncle in subsequent flowering periods.
Allow flowers to fall off naturally. Over time, these peduncles may elongate with each successive bloom. Adjust watering and fertilization based on the plant’s activity; if growth slows post-bloom, reduce watering frequency and suspend fertilization until new growth appears.