Lathyrus japonicus, commonly known as the beach pea or sea pea, is a perennial herbaceous plant that belongs to the family Fabaceae. Native to coastal regions of Asia and North America, it thrives in sandy beaches, dunes, and salt marshes.
The plant has a sprawling growth habit, with long stems that can reach up to 1 meter in length. Its leaves are compound, consisting of two leaflets and a tendril at the end of each leaf stalk. The flowers are purple or pink and have five petals arranged in a butterfly-like shape.
Lathyrus japonicus plays an essential role in coastal ecosystems by stabilizing sand dunes through its root system, which traps sand particles. It also serves as a food source for wildlife such as rabbits, deer, and birds.
Indigenous people have used Lathyrus japonicus for medicinal purposes for centuries, recognizing its anti-inflammatory properties. However, it is important to note that some species of Lathyrus contain toxic compounds that can cause paralysis if consumed in large quantities.
Overall, Lathyrus japonicus is a vital component of coastal ecosystems, offering both ecological benefits and medicinal properties when used responsibly under expert guidance.
Sea Pea has strong resistance to disease and is generally not prone to illnesses. However, it can be affected by pests and diseases present in its environment. These infections are generally not serious. For care, this plant needs moderate maintenance. It should be pruned regularly to keep a good appearance and promote healthy growth. Fertilizing can also help encourage flowering. Sea Pea is suitable for anyone with outdoor space, such as a garden or patio, and does not require extensive care experience. It may need more attention when grown indoors.
How to keep Lathyrus Japonicus.
Light
Sea Pea thrives in places where it can get several hours of uninterrupted sunlight each day. However, excessive sun can stress the plant. Because it originates from sun-exposed habitats, that sunlight supports its successful growth. A lack of ample sunlight can impede its development.
Water
Sea Pea flourishes in coastal regions, particularly in sandy soils with high salinity. While it prefers consistent moisture, it can tolerate dry conditions and only needs to be watered once a week. Thanks to its strong root system, Sea Pea efficiently absorbs water throughout the growing season, which helps it survive even when rainfall is unpredictable.
Temperature
Sea Pea occurs in habitats that can endure temperatures as low as 32 °F (0 °C) and as high as 90 °F (32 °C). To achieve the best growth, seasonal modifications may be required to accommodate these temperature ranges.
Fertilizer
For Sea Pea, the primary time to apply fertilizer is early spring, when flowers are developing. The appropriate fertilizer promotes better blooms and helps Sea Pea produce attractive flowers. Fertilizing in early spring ensures good flowers during the season and supplies energy for dormant growth phases.
Pruning
Sea Pea is a perennial plant known for its trailing growth habit and vibrant flowers. To promote branching, prune the plant in early spring, cutting back to 1-2 inches above a node. Light pruning will help maintain its shape and vigor. Be sure to monitor for pests and provide well-drained soil to ensure the plant's optimal health.
Botanical profile.
- Plant Type
- Herb, Vine
- Life Cycle
- Perennial
- Genus
- Lathyrus
- Family
- Fabaceae
- Hardiness Zone
- 3-7
- Mature Height
- 15 cm to 30 cm
- Mature Spread
- 61 cm
- Leaf Color
- Green, Gray
- Leaf Type
- Deciduous
- Flower Color
- Purple, Pink
- Flower Size
- 1.02 cm
- Bloom Time
- Early summer, Mid summer
- Planting Time
- Spring, Autumn
- Harvest Time
- Mid summer
Other names.
Reader questions.
What's the best way to water my Sea Pea plant?
To ensure the healthy growth of the Sea Pea plant, it is recommended to water it with filtered water that is at room temperature. Tap water may contain harmful particles that can affect the plant negatively. Moreover, it's important to use water that is at room temperature or slightly warmer to avoid shocking the plant, as it originates from warm environments. Overhead watering should be avoided as it can lead to foliage problems. Instead, water the plant by applying filtered room temperature water directly to the soil until it is completely soaked. This helps in moistening the roots and allowing them to spread through the soil for nutrient absorption.
Why should I put fertilizer on my Sea Pea?
The structure of the Sea Pea mainly consists of its leaves, so fertilization is crucial for ensuring that these leaves look great and function properly. By fertilizing the Sea Pea correctly, you can maintain consistent color and a healthy texture in the leaves. Additionally, fertilization also benefits the plant below the soil's surface by promoting the growth of new roots and maintaining the existing ones. This means that fertilization not only keeps the plant healthy in the present, but also improves its ability to absorb soil nutrients in the future.
What are the sunlight requirements for Sea Pea?
The Sea Pea requires different levels of sunlight depending on its stage and location. Full sun, defined as above 6 hours of sunlight, is necessary for its optimal growth, while it can also survive in partial sun, which is about 3-6 hours of sunlight. It's important to observe how sunlight moves through your garden to ensure that the Sea Pea is placed in a spot that provides the right balance of light and shade. This approach will guarantee the plant's happiness and successful growth.
What are the optimal growth temperatures for Sea Pea?
Sea Pea, or Lathyrus japonicus, thrives in environments that can sustain temperatures ranging from 32°F (0°C) to 90°F (32°C). It's important to make seasonal adjustments to accommodate these temperature preferences to ensure optimal growth. Sea Pea is highly cold-tolerant and does not require additional frost protection during the winter months. However, to prevent drought and water scarcity during winter and early spring, it is advisable to water the plant generously before the first freeze in autumn, ensuring the soil stays moist and enters a frozen state.
What should I do if I give my Sea Pea plant too much or too little water?
Overwatering is a common issue that can harm your Sea Pea plant. If your plant gets too much water, it may wilt, turn yellow, and even develop diseases like root rot, mold, and mildew. Underwatering is less likely, but still possible. In this case, the leaves may become brittle and brown. To prevent overwatering, it's important to notice the early signs and reduce watering immediately. If the soil doesn't drain well, replace it with a loose, well-draining potting mix. If your Sea Pea shows signs of needing more water, simply water it more regularly until the signs go away.
When should I put fertilizer on my Sea Pea?
If you grow your Sea Pea outdoors, it will send out new growth in early spring. This is a signal to start fertilizing. Usually, one application of fertilizer in the spring is enough, but if you want your Sea Pea to grow even more, you can feed it multiple times throughout spring and early summer. In this case, you can feed it once every month to a month and a half.
How can artificial lighting support Sea Pea growth indoors?
Indoor plants like Sea Pea require adequate lighting for optimal growth, especially when natural sunlight is insufficient. Artificial lights, such as LED lights, offer a vital solution. These lights should be able to provide the specific wavelengths of light that the plants need. Full sun plants require 30-50W/sq ft of artificial light, partial sun plants need 20-30W/sq ft, and full shade plants need 10-20W/sq ft. The light source should be placed 12-36 inches above the plant to mimic natural sunlight, and the duration should mimic the length of natural daylight hours, with most plants needing 8-12 hours of light per day.
What should I do if the winter temperature falls below -35°C for Sea Pea?
Sea Pea is extremely cold-tolerant, but its tolerance has a limit. Winter temperatures should ideally remain above -35°C. If temperatures dip below this threshold, you might not notice any immediate changes during the winter; however, there could be a decrease in sprouting or even no sprouting at all during spring. To address this, in spring, you should remove any parts of the Sea Pea that have failed to sprout, allowing the plant to recover and grow effectively.
How often should I give water to my Sea Pea?
If your Sea Pea plant is in a pot, the most accurate way to determine if it needs water is by checking the soil with your finger. If the top two to three inches of soil feel dry, it's a sign that you need to water it. If you have your Sea Pea plant growing outdoors in the ground, you can use a similar method to test the soil. Once again, if the first few inches of soil have dried out, it's time to water your plant. During the spring and early fall, this method usually means watering the plant about once a week. However, when the weather gets extremely hot, you may have to increase your watering frequency to twice or even more per week. Nevertheless, it's worth noting that mature and well-established Sea Pea plants have the impressive ability to withstand drought.
When is it not a good idea to put fertilizer on my Sea Pea plant?
During the late fall and winter, your Sea Pea will go into a dormant phase and stop producing new growth. It is important to avoid fertilizing your Sea Pea during this time. In the spring and summer, if you choose to fertilize multiple times, start reducing the amount of fertilizer as summer approaches because the growth rate of your Sea Pea will also slow down. It is never a good idea to fertilize your Sea Pea when it is unusually hot or when the soil is extremely dry, as this can stress the plant and cause it to die prematurely.
What are some common symptoms of light deficiency in Sea Pea?
Symptoms of light deficiency in Sea Pea can include smaller new leaves compared to the previous ones, leggy or sparse growth, increased leaf drop, slower or halted new growth, lighter-colored new leaves, and conditions such as chlorosis and sunscald. These symptoms indicate that the plant is not receiving adequate sunlight, which is essential for its health and growth.
How does Sea Pea react to high temperatures, and what are the solutions?
Sea Pea is not tolerant to high temperatures. Growth will halt, and the plant becomes more susceptible to rot when the temperature exceeds 32°C. To mitigate issues caused by high temperatures, trim away any sunburned and dried-up parts of the plant. Also, relocate the plant to a location that provides shade during the midday and afternoon sun, or use a shade cloth to create adequate shade. It's important to water the plant in the morning and evening to maintain soil moisture and prevent stress from heat.
