• German iris, white garlic and some geraniums produce nectar and bloom in March.flowers image by pearlguy from Fotolia.com
  
  Over 100 flowers produce nectar, but not all of them bloom during the month of March in the United States. Of those that do--which include white garlic, several geranium species and German iris--some can be found blooming in March as far away as Italy. Colors, shapes and U.S. Hardiness Zone regions may vary but there is one thing they all have in common: They provide nectar to butterflies, according to North Carolina State University.
  
  

White Garlic

• The genus Allium, species neapolitanum--also known as "white garlic" in the flower community--hails from the Lily flower family. White garlic benefits from partial to full sunlight with well-drained, but ordinary, soil. This white perennial flower blooms in March in Hardiness Zones 5 through 8 in the United States, according to "The Gardener's A-Z Guide to Growing Flowers from Seed to Bloom." The flower blooms in March elsewhere too, like Italy, according to the University of California at Berkeley. The flower produces nectar for butterflies, according to North Carolina State University. Because the blooms are produced so early in the year and the leaves eventually fade, some people plant white garlic in with the purple perennial,Tradescantia.
  
  

Geraniums

• Several of the geranium genus flowers, such as these species--cinereum (prefers full sun), macrorrhizum (partial or full sun) and phaeum (full shade)--bloom during the month of March. These nectar-producing flowers can be found growing successfully in U.S. Hardiness Zones 4 through 9 and prefer ordinary to moist soils. Color options include white, pink, blue and purple. These geranium flowers are perennials and make excellent ground cover flowers as well as border flowers, but they do not tolerate heat or humidity extremes. Geraniums can be both a tender and hardy perennial, depending on which species is chosen.
  
  

German Iris

• The germanica iris, also known as the German iris, is a hardy perennial bulb that flowers in March and provides nectar to butterflies too. This flower is available in blooms of blue, lavender, pink and white. It can be grown successfully in U.S. Hardiness Zones 4 through 9 and prefers full sunlight. Therefore, it is also used in xeriscaping. The German iris prefers ordinary soil, and it is considered one of the easiest perennials to grow. According to Stargazer Perennials, this particular iris may attract butterflies but it is deer-resistant, so you can plant it without fear if deer or a problem in your area.