Viburnum plants are prized for their diverse forms, attractive foliage, and often fragrant flowers and berries. Proper fertilization is important for their overall health and vigor, influencing growth and bloom production.
Why Fertilize Viburnum
Fertilizing viburnum plants replenishes essential soil nutrients. This supports robust growth, leading to denser, healthier foliage. Adequate nutrients also promote abundant flowering and fruit development, enhancing the plant’s ornamental appeal. A well-nourished viburnum exhibits greater resilience against environmental stressors and diseases.
When to Fertilize Viburnum
The optimal time to fertilize established viburnums is in early spring, just before new growth emerges. This ensures nutrients are available as the plant breaks dormancy and enters its active growth phase, supporting new leaves, stems, and flower buds.
For newly planted viburnums, delay initial fertilization until their second growing season. This allows roots to establish without being overwhelmed by concentrated nutrients. Once established, a light, balanced application can be considered in late spring or early summer if the plant shows signs of slow growth or pale foliage.
A second, lighter application can be beneficial in late summer or early fall for established plants, especially if they are in poor soil or show signs of nutrient deficiency. Avoid fertilizing too late in the fall, particularly in colder climates, as late-season fertilization can stimulate tender new growth susceptible to frost damage.
Choosing the Right Fertilizer
Understanding nutrient types and release mechanisms is important when selecting fertilizer for viburnums.
A balanced fertilizer, often indicated by an NPK ratio like 10-10-10 or 5-10-5, provides nitrogen (N) for leafy growth, phosphorus (P) for root and flower development, and potassium (K) for general plant vigor and disease resistance.
Slow-release granular fertilizers are recommended for viburnums. They provide a steady nutrient supply over an extended period, reducing nutrient leaching and over-fertilization. These formulations minimize root burn and require fewer applications.
Before choosing a fertilizer, a soil test provides insights into existing nutrient levels and pH. This helps identify deficiencies or excesses, allowing for a tailored approach. This ensures the plant receives what it needs, optimizing health and growth.
How to Apply Fertilizer to Viburnum
Proper fertilizer application ensures nutrient uptake and prevents plant damage. Water dry soil thoroughly a day before applying granular or liquid fertilizer to prevent root burn and aid nutrient absorption.
When using granular fertilizers, spread the recommended amount evenly around the viburnum’s drip line, the area beneath the outermost branches. Avoid placing granules directly against the trunk or main stems, as this can cause localized nutrient burn.
For liquid fertilizers, dilute the concentrate according to product instructions and apply as a drench to the soil around the plant’s base.
After applying fertilizer, water the viburnum thoroughly. This dissolves granular fertilizers, allowing nutrients to reach the root zone. For liquid applications, watering distributes the solution evenly and prevents surface concentration. Always adhere strictly to product label dosage rates, as over-application can harm the plant.
Common Fertilization Mistakes
One common mistake is over-fertilization, which can lead to nutrient burn, scorching foliage and damaging roots. Excessive nitrogen can stimulate leafy growth at the expense of flowers. Over-application also contributes to environmental runoff.
Applying granular fertilizer too close to the trunk or stems can cause chemical burns to bark and roots.
Failing to water adequately after application prevents nutrients from reaching the soil and can leave concentrated salts on the surface, harming roots.