Yellow jewelweed (Impatiens pallida) is a plant species that grows in Canada and the United States in wet soils. Yellow jewelweed blooms during midsummer and through the fall. Its flowers are almost completely pollinated by bees, which are attracted to their nectar.
I. Appearance and Characteristics
Impatiens pallida, with the common names pale jewelweed, pale touch-me-not, or yellow jewelweed, is a flowering annual plant in the family Balsaminaceae native to Canada and the United States. It grows in moist to wet soils, generally alongside the closely related Impatiens capensis, producing flowers from midsummer through fall.
The plant can grow up to 2 meters (6 ft 7 in) in height. The light green stems branch frequently and are smooth and slightly succulent. Leaves measure up to 10 centimeters (4 in) long and 5 centimeters (2 in) across and are alternate. They are simple, hairless, ovate, and have teeth on the margins.
The flowers are yellow, with reddish-spots on their faces, differentiating the plant from the similar Impatiens capensis, which has orange flowers. They are tube or funnel shaped and 3–4 centimeters (1–1.5 in) long, with nectar stored at a narrow spur at the back of the flower. The flowers cluster in small quantities among the upper leaves. After blooming, the flowers are replaced by a narrow seed pod up to 3 centimeters (1 in) long. When the seeds are ripe, they explode from the pod when touched, giving the plant its common name, touch-me-not.
Nectar spurs are tubular elongations of petals and sepals of certain flowers that usually contain nectar. Flowers of Impatiens pallida have nectar spurs which are thought to have played a role in plant-pollinator coevolution. Most of the nectar spurs of Impatiens pallida are perpendicular but some of them are curved.
These nectar spur flowers are either partially or completely pollinated by insects. The specific pollinator is determined by the curvature of the nectar spur. Since Impatiens pallida have perpendicular nectar spurs, bees are the main pollinators.
Yellow jewelweed is a toxic plant if ingested in large quantities. The stems, leaves, and flowers contain calcium oxide, a potentially poisonous chemical that can cause gastrointestinal distress. Symptoms can include abdominal pain, bloating, diarrhea, nausea, and vomiting. The biggest risk for poisoning occurs if the plant is consumed raw; the toxicity is greatly reduced during cooking. However, the trace amounts of calcium oxide in the heated leaves can cause complications for people with arthritis, gout, rheumatism, and kidney stones.
II. How to Grow and Care
Yellow jewelweed is characterized by its adaptability and minimal maintenance requirements. Preferring moist, well-drained soil and partial to full shade, yellow jewelweed thrives without needing excessive attention. Special care should focus on keeping the soil consistently moist without waterlogging and protecting yellow jewelweed from intense direct sunlight to prevent scorching its delicate foliage.
Sunlight
Yellow jewelweed thrives under partial sun, which involves receiving bright but indirect sunlight for the majority of the day. While yellow jewelweed tolerates full shade quite well, prolonged exposure to low light may result in leggy stems and fewer blooms, indicating a compromise in vigor and floral display. Remarkably adaptable, yellow jewelweed exhibits leaf adjustments such as increased leaf size in shadier conditions to maximize light absorption.
When cultivated outdoors, yellow jewelweed should be planted in locations that mimic its natural understory habitat, ideally under the dappled light of open canopies or on the north side of buildings.
Temperature
New Guinea impatiens (Impatiens hawkeri) and African Impatiens, also known as busy lizzie (Impatiens walleriana), are perennials. They can overwinter outdoors in tropical and subtropical areas and can be cultivated as annuals in other regions. When winter comes, you can move potted yellow jewelweed indoors. Garden balsam (Impatiens balsamina) is a true annual herbaceous plant. No matter how mild the climate is, it will complete its life cycle within a year and wither, so there is no requirement for winter temperatures.
The seeds of yellow jewelweed can germinate in the second year, so once they are planted in the garden you can basically see them every year. You can also collect its seeds, sow them indoors in the spring, cultivate seedlings, and then transplant them into flower pots or gardens when the weather gets warmer.
Yellow jewelweed prefers warm and humid climatic conditions, and the suitable temperature range for their growth is 15 to 25 ℃. When the temperature is below 5 ℃, their growth will be jeopardized. When the temperature exceeds 30 ℃, blooming will be affected and flowers will fall easily. Therefore, it is recommended to take some cooling measures. These plants need more water to keep the soil moist because drought is unfavorable for root and leaf growth.
Watering
Originating from moist environments, yellow jewelweed thrives in conditions that mimic its native habitat’s consistent moisture. This species exhibits a preference for evenly moist soil and is moderately drought-tolerant. Care should be taken to maintain this balance, watering every week to sustain its hydration needs. As an herbaceous plant often grown outdoors, yellow jewelweed benefits significantly from rainwater during its active growing season, which complements its water cycle and promotes robust growth.
Soil
Yellow jewelweed is not tolerant of drought or accumulated water. Thus, the best soil for them is fertile, loose, well-drained, sandy soil with a suitable pH of 6-6.5, which is slightly acidic. Never use damping soil as a culture medium. If compacted soil is found, be sure to loosen and mix it with other substrates to improve its permeability, which is good for yellow jewelweed growth.
Fertilizing
For healthy growth, yellow jewelweed benefits from fertilization, which encourages robust stems and vibrant blooms. A balanced nutrition fertilizer or high-nitrogen mix is optimal. Apply every 2-3 weeks during active growth, with reduced frequency in winter. Use half-strength solutions to prevent over-fertilization which can harm yellow jewelweed. Adjust timing and concentration to yellow jewelweed’s response, ensuring not to fertilize when the soil is dry. Both novice and experienced gardeners should monitor yellow jewelweed for signs of nutrient deficiencies or excess, and modify fertilization practices accordingly for this sensitive species.
Planting Instructions
It is best to sow yellow jewelweed every spring. You can sow them directly in the garden, or you can first plant them in a seedling tray. The culture medium can be selected from a slightly acid leaf mold or seed-starting mix. Spread the seeds on the soil, cover them with a layer of soil, and water again. Before the seeds germinate, a small amount of water can be provided in the morning or evening to keep the soil moist.
If the temperature is appropriate (about 25 ℃), yellow jewelweed will usually sprout in about 5 days. When the seedlings grow 3-5 true leaves or reach 10 cm high, they can be transplanted. If they are planted in a garden, the distance between each plant should be 20 to 30 cm. Before transplanting, you can apply a little base fertilizer. After transplanting, remember to water plants once to ensure healthy growth.
Pruning
Generally, when yellow jewelweed grows to 25 cm high, you can pinch, i.e. remove the buds, on the tops of branches. For thick, old branches, hard pruning is required to promote the re-germination of new branches, while the delicate branches can be lightly pruned as appropriate. Too-dense branches should be regularly thinned to ensure that the plant’s overall growth is even and that light can reach inside the plant to promote nutrient accumulation and blossoming.
Note that it is best to disinfect pruned yellow jewelweed to avoid wound infection and pests. Disinfectant can be applied with a small amount of potassium permanganate solution. Be sure to maintain air circulation and keep the surrounding environment clean.
Propagation
Yellow jewelweed thrives when propagated through sowing in early Spring. This species is relatively easy to propagate, with successful germination indicated by emerging seedlings. A moist environment and ample spacing ensure healthy growth.
Transplanting
For yellow jewelweed, the premier time to transplant is during the budding months of early to mid-spring, harnessing the mild weather for root establishment. Choose a shady spot with moist soil to mimic yellow jewelweed’s natural habitat for optimal growth.
III. Uses and Benefits
- Medicinal uses
Along with other species of jewelweed or “touch-me-not”, it is a traditional remedy for skin rashes.
- Culinary uses
Like Impatiens capensis, the young shoots can be boiled (with two changes of water) as a potherb, and the seeds are also edible.