Bulb sizes - What the numbers mean and what you should look for.

Understanding Flower Bulb Sizes: The Key to a Flourishing Garden

Let's delve into the fascinating world of flower bulb sizes. By understanding the anatomy of a bulb and the significance of its size, you can unlock lots of answers around creating a successful garden.

The Anatomy of a Bulb

To appreciate the importance of bulb size, it’s essential first to understand the anatomy of a bulb. Bulbs are in essence a storage device. They keep the plant alive whilst conditions are unfavourable. When you consider most bulbs originate from hotter climates and water is in short supply, bulbs can happily hide in the soil until cooler and wetter weather allows them to grow again. A typical flower bulb comprises the following parts:

• Basal Plate: The base of the bulb from which roots grow.
• Scales: The fleshy storage leaves that contain nutrients.
• Tunics: The outer skin that protects the bulb.
• Shoot: The embryonic plant that will develop into leaves and flowers.
• Bud: The central part that will bloom into the flower.

Decoding Bulb Sizes

When shopping for flower bulbs, you'll notice size numbers indicated on the packaging. These numbers refer to the circumference of the bulb in centimetres. For instance, a bulb labelled as 12/14 means it has a circumference of 12 to 14 cm.

The size of the bulb is a critical factor in determining the health and vibrancy of the flower it produces. Larger bulbs generally contain more stored food and energy, which translates into more robust growth and more impressive blooms.

There are many exceptions, but we prefer to provide size 11/12cm Tulips, 12/14cm Daffodils, 8/9cm Crocus, 16/17cm Hyacinths. Dont be alarmed if you have smaller bulbs. Some can naturally be smaller flowers, such as the species varieties.

Why Larger Bulbs Matter

Planting larger bulbs comes with several advantages:

• More Energy: Larger bulbs have more stored nutrients, providing a stronger start for the plant.
• Better Blooms: Bigger bulbs often result in larger, more numerous, and longer-lasting flowers.
• Increased Resilience: With more energy reserves, larger bulbs are better equipped to handle stressors such as drought or disease.

The Pitfalls of Planting Small Bulbs

The reason many bulbs appear to fail in the following year is that bulbs split into many smaller bulbs. If these bulbs are too small they may not have enought energy to flower. It is worth digging them up and selecting the bigger remaining bulbs for replanting. Each family of bulbs will have their own threshold for how big they need to be to flower. Smaller bulbs will eventually produce bigger flowers with the right care. These smaller splits will:

• Struggle to Establish: With less stored energy, small bulbs may struggle to establish themselves, leading to weaker plants.
• Produce Smaller Blooms: Flowers from smaller bulbs are often less impressive, both in size and number.
• Be More Susceptible to Stress: With fewer resources to draw upon, small bulbs are more vulnerable to adverse conditions.
• They can also dry out quicker, or succumb to rot in wet weather.

Should I buy the biggest Bulbs?

Bigger bulbs cost more. In my experience bulbs will use what they need. Excessively large bulbs dont need the extra food storage, you're paying for surplus starch! We would recommend selecting bigger bulbs for more complex flowers such as double tulips or multiheaded tulips as they will require the extra energy. We are always happy to answer questions about specific cultivars. 

At Peter Nyssen, we pride ourselves on offering a wide range of top-quality flower bulbs. Whether you're looking for stunning tulips, fragrant hyacinths, or graceful daffodils, our selection has been curated to ensure you get the best possible start for your garden. Explore our flower bulb collection and discover the difference that quality and size can make.