Hoya kerrii aka Sweetheart Plant

Hoya kerrii is a slow-growing climbing vine that can reach up to 4 meters (13 feet) when given a trellis or support structure to climb. The stems have a diameter of about 7 mm, and the distinctive heart-shaped leaves are approximately 6 cm wide and 5 mm thick. Growth is notably slow, so it may take several years for a plant to reach mature size. Single-leaf cuttings without stem tissue will remain as a single leaf indefinitely and will not develop into a full plant.

Hoya kerrii thrives in temperatures between 60-80°F (16-27°C), typical of most indoor environments. It should not be exposed to temperatures below 50°F (10°C), as this tropical plant has very little frost tolerance. Avoid placing it near cold drafts, air conditioning vents, or heating sources, as sudden temperature changes can stress the plant and cause leaf drooping.

The most reliable method is stem cuttings with at least 2-3 nodes and several sets of leaves. Remove leaves from the bottom half, optionally apply rooting hormone, and place in water or moist soil with at least one node submerged. While single-leaf cuttings can root and survive for years, they will never develop into a full plant because new growth requires stem tissue with nodes. This is why single-leaf 'Valentine' plants remain as a single leaf indefinitely.

Hoya kerrii prefers to be slightly root-bound, which actually encourages blooming. Repotting is typically only needed every 2-3 years due to its slow growth. Always repot in spring or summer, choosing a container only 1-2 inches larger than the current pot. Terra cotta pots are beneficial as they dry out faster, reducing the risk of root rot. Avoid repotting when the plant is in bloom.

Pruning is minimal for Hoya kerrii. You can trim long or leggy stems to encourage bushier growth, and remove any yellow or damaged leaves. However, avoid cutting off the short, bare flower stalks (peduncles), as the plant blooms from the same stalks year after year. Also avoid cutting long bare stems before leaves develop, as these precede new leaf or flower formation. Always use clean, sharp tools to prevent disease.

The thick, waxy leaves can accumulate dust over time. Wipe leaves gently with a damp cloth or give the plant an occasional shower with room-temperature water. If your plant has flowered, note that the nectar can make leaves sticky—this is natural and not a sign of pests. However, if stickiness appears without blooming, check for mealybugs or aphids hiding in leaf nodes and under leaves.

When Hoya kerrii blooms, the flowers produce a sweet fragrance often compared to honey or jasmine. The scent is typically most noticeable in the evening and at night. Not all plants flower with equal fragrance intensity—some may have only a faint scent while others fill a room with aroma. The flowers also produce abundant reddish-brown nectar, which can be sticky and may stain furnishings if the plant is positioned carelessly.

Several cultivated varieties exist beyond the standard green form. 'Variegata' (also called 'Albomarginata') has creamy-white or yellow margins around dark green centers. 'Reverse Variegata' is the opposite, featuring a bright yellow or chartreuse center with dark green edges. 'Splash' displays pale green speckles across the leaves. Variegated forms require slightly more light to maintain their coloring and may revert to green if light is insufficient.

Hoya kerrii can grow outdoors year-round only in USDA zones 10-12 where temperatures stay above 50°F (10°C). In these climates, grow it in dappled shade or bright indirect light, protected from direct afternoon sun. In cooler zones, it can be placed outdoors in summer but must be brought inside before temperatures drop. It naturally grows as an epiphyte in tropical rainforests, climbing trees with aerial roots.

Hoya kerrii flowers are pollinated by insects (entomophilous pollination). The star-shaped blooms produce abundant reddish-brown nectar that attracts various pollinating insects. Indoors without pollinators, flowers will not produce seed but will still provide their ornamental value and fragrance for several weeks before naturally fading.

The most common cause is overwatering, which leads to root rot and multiple leaves yellowing at once (leaves may feel soft or mushy). Underwatering causes individual leaves to yellow and feel dry. Other causes include too much direct sunlight, nutrient deficiency (fertilize monthly during growing season), environmental stress from recent moving or repotting, or simply natural aging of oldest leaves. Allow soil to dry completely between waterings and ensure proper drainage.

Brown leaf tips typically indicate low humidity or inconsistent watering (underwatering). Brown spots or crispy patches often result from sunburn caused by too much direct sunlight. Overwatering can also cause browning, usually accompanied by soft, mushy texture. If the entire plant shows 'thinning, brown or wrinkled leaves,' it may be drying out too much between waterings. Improve humidity with misting or a pebble tray, and move away from direct sun.

Drooping is most often caused by watering issues. Underwatering causes leaves to lose turgor pressure and droop—check if soil is bone dry and water thoroughly. Overwatering can cause root rot, making roots unable to absorb water even when wet—check for mushy stems and yellowing. Other causes include low humidity, cold drafts, sudden temperature changes, or root-bound conditions needing repotting. Maintain temperatures of 60-80°F and humidity around 40-60%.

Mealybugs are the most common pest, appearing as white cottony masses in leaf nodes and under leaves. Aphids and spider mites may also occur, especially in dry conditions. Treat infestations by wiping with rubbing alcohol or spraying with neem oil or insecticidal soap every few weeks until eliminated. Root rot from overwatering is the main disease concern—prevent it with well-draining soil and allowing soil to dry between waterings. The sweet flower nectar can attract pests during blooming.

Slow growth is natural for Hoya kerrii—it's inherently a slow-growing species. However, if growth seems abnormally slow, check that it's receiving enough bright indirect light. Insufficient nutrients can also limit growth, so fertilize monthly during the growing season with a balanced houseplant fertilizer. Overwatering and root rot will stunt growth. Note that single-leaf plants without stem tissue will never grow additional leaves, regardless of care.