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Drought Tolerance of Bedding Plant Annuals

Project Leader: Alex Gerace, Welby Gardens, Denver

Other Participants: Tagawa Garden Center, Echter's Garden Center

Technical Advisors:

  • David Hartley, CSU Department of Horticulture and Landscape Achitecture
  • Steven Newman, CSU Department of Horticulture and Landscape Achitecture
  • James Klett, CSU Department of Horticulture and Landscape Achitecture

Project Year: 2003

Annual Report Summary

The objective of this experiment is to determine how much irrigation water is necessary to maintain healthy bedding plants. Plants were irrigated at five different levels, 100% of Et (blue grass), 75% Et, 50% Et (X-rated), 25% Et (XX-rated), and 0% Et (XXX-rated, no additional water after a two week establishment period). Plants that performed well down to 0% Et or XXX-rating (natural rain fall after an establishment period) include: Petunia hybrida 'Merlin White' and Verbena x speciosa 'Imagination Blue'. Plants that performed well down to 25% Et or XX-rating, receiving no more that ½ inch of water/week (8 to 14 days between waterings) include: Rudbeckia hirta 'Indian Summer', Tagetes erecta (African Marigold) 'Inca Yellow' and Zinnia elegans 'Dreamland Red'. Plants that performed well down to 50% Et or X-rating, receiving no more than 1 inch of water/week (5 to 7 days between waterings): Lobularia maritima (Sweet Alyssum) 'Carpet White', Antirrhinum majus (Snapdragons) 'Sonnet Yellow', Catharanthus roseus (Vinca) 'Peppermint Cooler', Dianthus hybrida 'First Love' , Lobelia erinus 'Cobalt Blue', Pelargonium hortorum (Geranium) 'Kim Red', Portulaca grandiflora (Moss Rose) 'Sundial Mix', Salvia farinacea 'Rhea Blue', Senecio cineraria (Dusty Miller) 'Silver Dust', Tagestes patula (French Marigold) 'Bonanza Yellow', and Zinnia angustifolia 'Crystal White'. Plants that performed well at 75% Et (3 to 4 days between waterings) include: Viola x wittrockiana (Pansy) 'Crown Gold'. Plants that performed best at 100% Et (2 to 3 days between waterings) include: Begonia x semperflorens 'Vodka Red-Bronze' and Impatiens walleriana 'Tempo White'.

Click here for the full text of the 2003 Annual Report (Word Document) including more detailed information on each plant species (note: this is a large file and may take a few minutes to download).

Colorado State University College of Agricultural Sciences Department of Horticulture and Landscape Architecture