What size bulb should I purchase?

By: Mariel Bacci
February 17, 2021
What size bulb should I purchase?
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What can you expect out of your bulb, and how many leaves or flowers will it produce when it sprouts? What size will my bulb be and why does that make a difference? Let's dig a little deeper to find out what surprises lay in store!

Amaryllis Bulb Sizes

Amaryllis bulbs

Amaryllis are showstoppers and come in a variety of colors. Centimeter measurements are the standard for interpreting sizing on Amaryllis bulbs. The widest part of the bulb or its circumference is the number to notice. They can range from 8 cm to 34/36 cm—consequently, the bigger the bulb, the thicker and sturdier stems and flowers they produce. Larger bulbs are more mature and store more energy, and therefore make more blooms or leaves. Of course, soil, light, rain, and fertilizer will affect the performance as well, but here is an approximate estimation of what to expect out of your amaryllis bulb sizing:

26/28 cm-1 stalk (occasionally 2) with 3-4 blooms

28/30 cm-1-2 stalks with 3-4 blooms per stalk

30-32 cm-2 stalks with 4-5 blooms per stalk

32/34 cm-2 stalks (occasionally 3) with 4-5 blooms

34/36 cm-3 stalks with 4-5 blooms per stalk

Planting tips for Amaryllis: 

  • Over time, your amaryllis bulbs will grow and eventually produce bulblets, so more blooms are on the horizon! To make a longer show of these gorgeous blooms, stagger the planting time out, so you have each bulb blooming on varied weeks and not all at once! Or plants several bulbs together for a 'fireworks' show of sorts on your dining table! 

Caladium Bulb SizesCaladium bulbs

Caladiums look like miniature versions of Elephant ears with colorful variations. Grade numbers measure caladium sizing standards. The higher the grade number, the smaller the tuber! So to get more lush, colorful leaves on your caladium, you want to aim for the #1 or Jumbo size. This size doesn't equate to bigger leaves or taller stems, as some might think but more leaves, which is like having more blooms! And that's why you get these caladium tubers. Their colorful leaves are like having flowers all season long without deadheading! For planting distance, we suggest planting according to the leaf's production for each size bulb, which you can find in the chart below. 

Grade Bulb Diameter Planting Apart 

#3        1/2"-1" 1"-2"

#2        1"-1 1/2" 2"-4"

#1        1 1/2"-2 1/2" 4"-7"

Jumbo  2 1/2"-3 1/2" 8"-10"

Planting tips for Caladiums: 

  • Caladiums have what horticulturists call eyes or terminal buds. From these eyes or buds come larger, more dominant shoots. Wise gardeners desire to remove these by de-eyeing them. The reason to do this is to prevent apical dominance, so they become bushier and more uniform in their leaf production, which is a really good thing. Like getting more bang for your buck! You can do this with flowering perennials to make more bloom production too! This is one of the many tricks we have up our garden gloves! Remove about 1/8th to 1/4" of the protruding buds with a small knife and leave a little divot. Remove each bud that is visible with this method. Let the tuber dry and heal for 24-36 hours in a well-vented area. This trick aids in a fuller plant, giving you a showier display in the garden or container. 
Canna Lily Bulb Sizes

Canna lilies

Canna lilies are the most colorful and striking with various warm colors, but the palm-like leaves are often just as colorful. When the soil temps are at 60°F in late spring or early summer, and after the last frost, it's time to plant! Or you can get a head start and plant in pots and keep indoors or a greenhouse until time for the big reveal. 

Canna rhizomes are sized by the number of eyes or buds they have. The more eyes, the larger the rhizome is, and hence, more blooms and leaves will sprout. Plant these 2-3 inches deep (with the eyes/buds facing upward) and two times the width of the rhizome. Water initially and then be sparing with the irrigation to prevent root rot until sprouts appear above ground. Shoots will take about three weeks to emerge. 

Size Plant Spacing 

1/2 eyes 2 feet 

2/3 eyes 2 1/2 feet 

3/5 eyes 3 feet 

Plant in full sun where the spot gets 6-8 hours of sun a day. If you are in a hotter climate, they can tolerate some shade in the afternoon heat. Canna lilies enjoy consistent moisture (but not soggy) each week, therefore water three times a week if the average rainfall isn't plentiful. 

Planting tips for Canna Lilies:

  • Plant in full sun where the spot gets 6-8 hours of sun a day. If you are in a hotter climate, they can tolerate some shade in the afternoon heat. Canna lilies enjoy consistent moisture (but not soggy) each week, therefore water three times a week if the average rainfall isn't plentiful. 
  • After blooming, prune the stalk down to the plant's base to stimulate more stems and blooms.
  • They have an upright habit that can extend up to 6 feet tall, making it a lovely screening plant or a bold statement in container plantings. And bonus, they attract hummingbirds to the garden! 
  • Create a rich soil environment when planting initially. Add organic composted materials as well as manure mixed into the soil. Use a 10-10-10 fertilizer. Apply in early spring by scratching the soil's surface around each plant and mixing the fertilizer into it. Continue to apply each month until six weeks before the first frost in the fall. Water in the fertilizer with a nozzle set to the light shower setting to decrease wash away.

Elephant Ear Bulb Sizes

Elephant Ears-Upright (Alocasia) & Elephant Ears-Common (Colocasia)

Create your own tropical rain forest with these lush foliage bulbs. Use them in the garden landscape or containers flanked around a pool and patio area. The bulbs are quite large and vary from 13-17+ inches in circumference. Their growth height can extend to 6 feet tall and wide, making them a brilliant screening plant in the summertime. The bigger the bulb circumference, the more foliage on display. See our recommendations for the bulb sizing to the spacing between bulbs when planting in the garden beds. 

Elephant Ears-Upright (Alocasia)

Sizing   Plant Spacing

13-15 inches 5 ft.

17+ inches 6 1/2 ft.

Elephant Ears-Common (Colocasia)

Sizing Plant Spacing

5-7 inches 2 ft.

11-13 inches 4 ft. 

Planting tips: 

  • Plant with the flat end of the bulb (roots) downwards and the tip facing upwards in loamy soil full of organic matter for good drainage. Keep the bulbs consistently moist throughout the season.