Growing Lathyrus: Sweet Pea and Everlasting Pea

Growing Lathyrus - Standard Substrate, Sunny Location or Partial Shade, Moderate Watering

Introduction to Growing Lathyrus

Lathyrus, commonly known as sweet pea or everlasting pea, is a charming climbing plant that brings vertical beauty to any garden. Whether you're cultivating the fragrant annual sweet pea (Lathyrus odoratus) or the perennial everlasting pea (Lathyrus latifolius), these plants are relatively undemanding and reward gardeners with abundant blooms throughout the growing season.

Substrate Requirements for Lathyrus

One of the great advantages of growing Lathyrus is its adaptability to standard substrate. These plants thrive in regular garden soil without requiring specialized growing media.

Ideal Soil Composition

• Well-draining soil - Lathyrus doesn't tolerate waterlogged conditions
• Moderately fertile - Standard garden soil enriched with compost works perfectly
• pH neutral to slightly alkaline - pH 6.5-7.5 is optimal
• Loose texture - Allows roots to penetrate easily and establish quickly

Soil Preparation Tips

Before planting, incorporate well-rotted compost or organic matter into the soil to improve structure and nutrient content. If your soil is heavy clay, add sand or perlite to enhance drainage. For container growing, use a standard potting mix with added compost.

Light Requirements: Sunny Location or Partial Shade

Lathyrus demonstrates flexibility when it comes to light requirements, making it suitable for various garden positions.

Sunny Location (Preferred)

For the most abundant flowering, position your Lathyrus in a sunny location receiving at least 6-8 hours of direct sunlight daily. Full sun encourages:

• Maximum flower production
• Stronger stems and more vigorous growth
• Richer, more intense flower colors
• Better disease resistance

Partial Shade Tolerance

Lathyrus also performs well in partial shade, particularly in regions with hot summers. In these conditions:

• Plants benefit from afternoon shade protection
• Flowering may be slightly reduced but still satisfactory
• Foliage remains lush and green
• The blooming period may extend longer in cooler conditions

Avoid deep shade, as this will result in leggy growth and minimal flowering.

Watering Schedule: Moderate Watering

Proper watering is essential for healthy Lathyrus plants. The key principle is moderate watering - neither too much nor too little.

Watering Guidelines

• Consistent moisture - Keep soil evenly moist but never waterlogged
• Deep watering - Water thoroughly once or twice weekly rather than frequent shallow watering
• Morning watering - Reduces disease risk by allowing foliage to dry during the day
• Adjust for weather - Increase frequency during hot, dry periods; reduce during cool, wet weather

Signs of Incorrect Watering

Overwatering symptoms:

• Yellowing leaves
• Root rot
• Wilting despite wet soil
• Fungal diseases

Underwatering symptoms:

• Drooping leaves and stems
• Reduced flowering
• Premature bud drop
• Stunted growth

Support and Training

As climbing plants, most Lathyrus varieties require support structures:

• Trellises - Ideal for annual sweet peas in borders
• Obelisks - Perfect for creating vertical focal points
• Fences and walls - Natural supports for perennial varieties
• Netting - Economical option for cut flower production

Install supports at planting time to avoid disturbing established roots later.

Feeding Requirements

While Lathyrus grows well in standard substrate, periodic feeding promotes better flowering:

• Apply a balanced liquid fertilizer every 2-3 weeks during active growth
• For perennial varieties, apply slow-release granular fertilizer in early spring
• Avoid high-nitrogen fertilizers which promote foliage at the expense of flowers
• Consider potassium-rich feeds to encourage abundant blooms

Deadheading and Maintenance

Regular maintenance ensures prolonged flowering and healthy plants:

• Deadhead regularly - Remove spent flowers to prevent seed formation and encourage continuous blooming
• Monitor for pests - Watch for aphids, particularly on new growth
• Check tendrils - Guide young growth onto supports as needed
• Remove damaged foliage - Maintains plant health and appearance

Planting Times and Methods

Annual Sweet Peas

• Sow seeds in autumn or early spring
• Pre-soak seeds for 24 hours or nick seed coat to improve germination
• Plant outdoors after last frost when soil has warmed

Perennial Varieties

• Plant container-grown plants in spring or autumn
• Divide established clumps every 3-4 years
• Space plants 30-45cm apart

Common Problems and Solutions

Powdery Mildew

White powdery coating on leaves. Ensure good air circulation, avoid overhead watering, and position in locations with adequate sunlight.

Aphids

Small green insects clustering on growing tips. Spray with water or use insecticidal soap for severe infestations.

Poor Flowering

Usually caused by insufficient light, too much nitrogen, or failure to deadhead. Adjust growing conditions accordingly.

Seasonal Care Summary

Spring: Plant out, provide support, begin regular watering and feeding

Summer: Maintain consistent moisture, deadhead regularly, monitor for pests, continue feeding

Autumn: Allow perennials to die back naturally, collect seeds from annuals if desired

Winter: Mulch perennial varieties for protection, plan next season's plantings

Conclusion

Growing Lathyrus successfully comes down to providing three fundamental conditions: standard substrate enriched with organic matter, a sunny location or partial shade position, and moderate watering that keeps soil consistently moist without waterlogging. These relatively undemanding plants reward minimal care with spectacular displays of colorful, often fragrant flowers that are perfect for cutting or enjoying in the garden. Whether you choose annual sweet peas for their intense fragrance or perennial varieties for their long-term presence, Lathyrus brings vertical interest and cottage garden charm to any planting scheme.