Verbena bonariensis – planting and care

Scientific name: Verbena bonariensis

Family: Verbenaceae, Verbena family

One of the great strengths of the giant verbena is its excellent drought tolerance. This means you can actually grow it in a pot and overwinter it indoors. If planted outdoors in beds, it tends to self-seed, but keep in mind that Verbena bonariensis doesn't have the best hardiness. In very mild climates, it may return year after year, but for most of us here in Norway, it should be considered an annual plant.

Nonetheless, Verbena bonariensis is popular among pollinators. The decorative flower clusters attract butterflies and bees, while also creating a beautiful display of color in the garden. The blooming period usually lasts from summer to fall – and the flowers are small, purple-blue or pink, sitting on long, upright stems.

• Sunlight
  Verbena bonariensis thrives best in sunny environments and requires many hours of sunlight each day to grow well.

• Watering
  While Verbena bonariensis is drought-tolerant, it should be watered regularly when newly planted or during extended dry periods to keep it healthy.

• Fertilizer
  In general, Verbena bonariensis is quite low-maintenance when it comes to fertilizer. If you notice the plant growing and blooming healthily without any fertilizer, there’s no need to add anything. Use manure if necessary.

• Pruning
  Keep the plant neat and full of life by cutting off dead flowers, which promotes new blooms. If you want a bushier growth, you can trim the stems a little in the spring. If you're overwintering the plant, it should be pruned in early spring.

Verbena bonariensis can be overwintered in a pot. It is not frost-tolerant, so you should place the pot in a sheltered spot where the plant can still receive sunlight. This helps protect it from freezing temperatures while ensuring it gets the light it needs to survive the winter.

If Verbena bonariensis grows beyond its boundaries or loses vitality, you can divide it in the spring or fall to create new plants. This also promotes better air circulation and helps prevent diseases.

Verbena bonariensis is often grown as an annual plant, but it can still self-seed in the garden. The seeds can survive under the snow, and new plants may appear the following summer.

The plant is usually grown from seed. It can take some time for the seeds to germinate, so it's a good idea to start pre-cultivating indoors as early as January. Sprinkle the small seeds on top of the soil, and cover them with a layer of Vermiculite – this helps maintain consistent moisture around the seeds. Water gently and cover with plastic, making sure to add ventilation holes so moisture can escape. It’s beneficial to place the newly sown seeds under a grow light to ensure they receive plenty of light. Be patient and wait for the seeds to sprout and grow. Once the young plants have developed 2 to 3 pairs of leaves and are large enough to handle, you can prick them out – moving each little plant into its own pot.

Verbena bonariensis is planted in the spring, after the risk of frost has passed. Choose a sunny location with well-drained soil. Water generously during the first few weeks, and then as needed.

• Placement
  Verbena bonariensis thrives best in full sunlight. Place it in a location where it will receive at least 6-8 hours of direct sunlight daily. While it can tolerate some shade, it blooms best in the sun. If planting multiple plants, ensure they are spaced adequately apart.

• Digging the hole
  Dig a hole that’s large enough to accommodate the root ball and allow a little extra room beneath. Place the plant in the hole, ensuring that it sits at the same level as it was in the pot. Carefully fill in around the root system with soil, pressing lightly to eliminate any air pockets.

• Soil
  Verbena bonariensis prefers well-draining soil. If your soil is heavy and clay-like, mix in bark mulch to improve drainage. If it's sandy, you can add some compost to enrich it. Avoid overly wet soil, as excess moisture can harm the roots.

• Fertilizer
  Verbena bonariensis typically doesn't require much fertilizer. If the soil is light and well-drained, it usually provides enough nutrients for the plant. However, if the soil is nutrient-poor, you may need to add some fertilizer or compost at planting time.

• Watering
  Water generously when planting, ensuring both the root ball and the hole are well-watered. Keep the plant well-watered for the first couple of weeks until it becomes established. After that, water the plant during dry spells. Once the plant is settled, it’s relatively drought-tolerant.

You can definitely choose to grow Verbena bonariensis in a pot. The challenge with potted plants is that the soil dries out faster, and nature can't regulate the microconditions as it does in a flower bed. Therefore, it’s important to ensure that the pot is large enough to accommodate the plant and that the root system has enough space to develop over time.

Use a well-draining soil mix suitable for ornamental plants or perennials. Because the nutrients in pots can be used up faster than in garden beds, it may be necessary to fertilize Verbena bonariensis in a pot.

Water as needed – the plant tolerates drought, but the soil should not dry out completely. The soil in pots dries out faster than in garden beds, so feel the soil with your fingers or gently lift the pot to see how light it is. A dry pot is lighter than a moist one. Make sure the pot has drainage holes at the bottom to avoid overwatering and reduce the risk of root rot.

TIPS FROM THE EXPERTS:

- Jennie: Gardener with a passion for garden design and fruit trees. Apple trees are her favorite!

- Nadja: Horticulturist and landscape planner with a special interest in potted plants, particularly climbing plants like Philodendron and Monstera.

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