Iowa State University
INDEX A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Zinnias

This article was published originally on 7/19/2002

Zinnias are special garden plants for several reasons. Who doesn't like zinnias? Who doesn't remember them growing in your grandmother's summer garden? Who hasn't collected a few flowers to put in a vase on the windowsill? And besides, how many other plants can you think of that have a name that begins with a 'z'? Combine the above remembrances and uses with a dizzying array of flower colors, various heights to suit any purpose, and an almost indestructibility in the garden, and zinnias are worthy of a one-of-a-kind reputation.

There are several species that contribute to this outstanding reputation. By far the most widely known species is Zinnia elegans. This native of Mexico is the one your grandmother grew. It has the widest range of flower size (1/2inch to 2 inch diameter), flower colors (every color except true blue, brown, or black), flower forms (single, double, cactus, etc.), and heights (8 inches to 4 feet tall). But alas, such variety comes with a price. Z. elegans requires regular deadheading and consistent moisture to keep it blooming all summer. If it is not planted in a sunny location with good air circulation, it is often infested with powdery mildew or another disease. Finally, even though it is native to Mexico, Z. elegans is not the most heat tolerant of the zinnia species available. Some of the many commonly available cultivars include:

Name Flower Form Flower Colors Flower Size
(inches)
Plant Height
(inches)
Candy Stripe Dbl W,rs, rd, pk striped 4 24
Envy Semi G 2 30
Giant Cactus Dbl quilled Rd, o, pk, y, rs, sm, w 4-5 30
Sun Dbl Rd, y, w, sc 4-5
Ruffles Dbl ball-shaped Rd, pk, y, w, o 3 24-28
Liliput Dbl-pompon Pr, o, rs, y, sc, w 1-2 12-15
Peter Pan Semi Pr, pk, y, sc, w 3 12
Whirligig Semi-patterned Pk, rd, o, sc, w 3-4 20
Oklahoma Semi Y, pk, sm, sc, w 1-2 30-40
Small World Dbl Pk, rd 2 12-14
Thumbelina

Semi = semi double, dbl = double
Rd = red, rs=rose, pk=pink, pr=purple, y=yellow, o=orange, sc=scarlet, sm=salmon, w=white

Another recognizable species is Z. angustifolia. This smaller zinnia is native to the Southeastern United States and Mexico and is know for its durability in the garden. Unlike Z. elegans, Z. angustifolia requires little deadheading and is highly resistant to powdery mildew and other diseases. It's legendary heat tolerance more than makes up for the limited palette of flower colors and plant heights. In fact, a couple of cultivars were awarded the distinction of All-American Selection Winners.

Name Flower Colors Flower Size
(inches)
Plant Height
(inches)
Profusion Series Orange, White, Cherry 2 12-15
Crystal White White 2
Star Series Orange, Gold, White 1-2 12

A lesser-known zinnia species, Z. haageana, is gaining in popularity. It is smaller like Z. angustifolia and is equal in its resistance to disease. However, some deadheading is required to keep plants blooming profusely all summer. While there is only one cultivar or series common in the trade, it is more than worthy of consideration in the garden.

Name Flower Colors Flower Size
(inches)
Plant Height
(inches)
Persian Carpet Red, gold and mahogany bicolors 2 16

All zinnias prefer full sun and well-drained soils. If properly planted and maintained, even the most difficult cultivars will remain attractive. All are wonderful cut flowers and easily brighten any windowsill. Continue the legacy: find a few places in your garden to plant zinnias.



This article originally appeared in the July 19, 2002 issue, pp. 100-101.

Year of Publication: 
2002
Issue: 
IC-487(18) -- July 19, 2002

Related information: