Delphiniums, the majestic flowers that grace our gardens with their vertical splendor, are a beloved feature of the summer landscape. But as July arrives, these cottage garden favorites often face a challenge: the intense heat and soaring temperatures can cause their blooms to fade, stems to droop, and foliage to struggle. It's a critical time for gardeners to step in and ensure these plants not only survive but thrive, potentially rewarding us with a second flush of flowers. Here's a deep dive into the essential care tasks that will keep your delphiniums healthy and vibrant throughout the season.
The Art of Deadheading
Deadheading is the cornerstone of delphinium care in July. It's a simple yet powerful technique that can significantly impact the plant's performance. By removing faded flower spikes as soon as they've finished blooming, you're essentially telling the plant to focus its energy on producing new growth rather than seeds. This encourages a second, lighter flush of flowers, ensuring your garden remains a vibrant spectacle.
Rachel Bull, Head of Gardens at Homes & Gardens, emphasizes the importance of this practice: 'Deadheading is the most crucial task for delphiniums in July. Many varieties will reward you with a second, lighter flush of flowers if you cut back the spent spikes before the plant starts putting energy into seed production.'
When deadheading, it's essential to use sharp pruning shears to make clean cuts. This reduces the risk of damage to the stems. Fiskars Bypass Pruning Shears are a reliable choice, available at Amazon and The Home Depot. Additionally, if your delphiniums have reached their full height, it's a good idea to check and adjust their supports while pruning.
Deep Watering: A Life-Giving Practice
Delphiniums appreciate consistently moist soil, but they don't tolerate prolonged drought well. During heatwaves, deep watering becomes a lifeline for these plants. Aim to soak the soil once or twice a week, depending on rainfall and soil type. This ensures that the moisture reaches the deeper roots, helping the plants cope with rising daytime temperatures.
Bull advises, 'Deep watering is far more effective than frequent, shallow watering during heatwaves. It's a simple yet powerful way to keep your delphiniums healthy and vibrant.'
Using a Gilmour Heavy Duty Adjustable Metal Hose Nozzle, available from Amazon and Walmart, allows for easy switching between gentle showers for borders and stronger streams for other yard tasks. Additionally, adding a layer of compost or organic mulch around the base of the plants helps conserve soil moisture and regulate root temperatures, reducing the need for frequent watering.
Support Systems: A Wind-Resistant Defense
July's intense thunderstorms can take a toll on tall delphinium flower spikes, making them vulnerable to strong winds and heavy rain. It's crucial to ensure that your supports are still doing their job. Even if you've staked the plants earlier in the season, now is the time to double-check their stability.
Ecostakes Bamboo Garden Stakes from The Home Depot are a versatile and affordable option for supporting tall delphiniums. Soft garden ties can also be used to gently secure stems without causing damage. The key is to allow the stems enough room to move naturally without rubbing against the supports.
Feeding for Growth
After deadheading the first flush, consider giving your delphiniums a light feed. A balanced fertilizer or one slightly higher in potassium is ideal, as it helps plants recover without promoting excessive soft, leafy growth that can struggle in hot weather. Miracle-Gro Water Soluble Bloom Booster Flower Food is a popular choice, available on Amazon.
Remember to water well after feeding, especially in high temperatures, to ensure the nutrients reach the root zone without scorching stressed roots.
Powdery Mildew Prevention
Hot days followed by humid nights create the perfect conditions for powdery mildew, a common issue for delphiniums in midsummer. Good airflow is your best defense. Remove any badly affected leaves, avoid overhead watering, and ensure neighboring plants aren't overcrowding each other.
Safer Brand Insect Killing Soap, available on Amazon, is a gentle yet effective solution for tackling soft-bodied summer garden pests while being safe for ornamental plants.
Conclusion: A Second Act for Delphiniums
Caring for delphiniums in July is a delicate balance of deadheading, watering, supporting, feeding, and monitoring for pests. By avoiding common mistakes like allowing plants to dry out and cutting back healthy foliage too early, you can ensure your delphiniums not only survive the heat but potentially reward you with a second, vibrant display of flowers.
In my opinion, the key to success is a combination of timely care and a deep understanding of your garden's unique conditions. With a little attention and love, your delphiniums will thrive, adding a touch of cottage garden charm to your landscape well into the late summer months.
