Amaryllis Bulb Size: What the Measurements Mean and Why They Matter
If you’ve shopped for amaryllis bulbs, you may have wondered whether there’s really much difference between one bulb and another. Do you need to care about the size of the bulb?
To get a good value for your money, the answer is yes. With amaryllis there’s a clear relationship between bulb size and performance.
Amaryllis bulbs are sized by measuring (in centimeters) around the widest part of the bulb. In the photo below, the bulb on the far right measures 26/28 centimeters in circumference. The largest one on the far left is a full 8 cm larger, measuring 34/36 cm.
Plants don’t always behave like we expect them to, but as a general rule, the size of an amaryllis bulb tells you how many stems and flowers it will produce.
Bulbs are storage vessels, and the bigger the bulb, the more stored energy it has. This is why a small amaryllis bulb can produce a single stem with 2 or 3 flowers, while the largest size bulbs is able to produce 3 stems, each with 4 or 5 flowers.
Stem strength also varies depending on bulb size. Larger bulbs produce thicker, stronger stems.
Here are how many stems and flowers each size bulb is likely to produce:
26/28 cm – 1 stem (occasionally 2) with 3 to 4 flowers
28/30 cm – 1-2 stems with 3-4 flowers per stem
30/32 cm – 2 stems with 4-5 flowers per stem
32/34 cm – 2 stems (occasionally 3) with 4-5 flowers per stem
34/36 cm – 3 stems with 4-5 flowers per stem
This is another factor that plays into bulb size and price. An amaryllis variety that is widely available and easy to propagate is usually less expensive than a new variety that is in short supply or is difficult to propagate. It’s the same reason a common peony variety costs far less than one that was recently introduced by its breeder.
You may also notice that not all amaryllis varieties are available in every bulb size. For less common varietes, the sizes and quantities are limited by demand and by the growing season.
So if a flashy new amaryllis variety catches your eye, you can expect to pay a bit more for it. Shown below is a relatively new introduction, ‘Benfica.’
Getting Creative with Amaryllis
It’s important to know that there’s nothing wrong with smaller-size bulbs. In fact, planting a couple 26/28 cm bulbs together can give you a great look. You could add a few paperwhites or a couple pots of cyclamen as companions. Or you could pot up several bulbs and plan to use them as cut flowers.
When you want to get the biggest flowers and the most blooms from a single bulb, purchase the largest size bulb you can find. Since these bulbs send up multiple stems, usually a week or two apart, they will also give you the longest possible show.
Other Facts About Amaryllis Bulbs
• Jumbo amaryllis bulbs, which are at least 34/36 cm, are bigger because they’re a full year older than the next size down. It costs more to keep these bulbs “on the farm” for an extra year and that’s why the price is higher.
• Some amaryllis varieties naturally produce smaller than normal bulbs. These include Cybister amaryllis, like ‘Evergreen‘, which have narrow, spidery petals, and miniature amaryllis, which have short stems and half-size flowers. The size of these bulbs shouldn’t be compared to full size varieties.
All amaryllis bulbs produce big, beautiful flowers. To make sure you get a good value for your money, pay attention to bulb size. The bigger the bulb, the more flowers you’ll get!