Almost all Amaryllis (Hippeastrum) forced in the U.S. and Canada by either homeowners or commercial forcers are grown overseas. In order to comply with USDA/APHIS plant quarantine regulations, all bulbs must be free of soil. Thus, they are washed once or twice prior to packing and shipping. As a result of this treatment, the bulbs arrive with only basal roots and no secondary roots. Therefore, over the past year, 2 hand made mixes and 7 commercially prepared mixes were evaluated using 2 cultivars each of Swaziland- and Dutch-grown bulbs. The effects of these media on forcing characteristics, e.g. total plant height, leaf length, flower number, etc. were examined. Also, the influence of the various media on basal root growth and formation of new secondary roots was measured. The results of these 2 studies will be presented.
A. A. De Hertogh and M. Tilley
A.A. De Hertogh and M. Tilley
The Swaziland-grown Hippeastrum bulbs `Summertime' and `Sun Dance' reached the market and flowering stages of development in fewer days than the Dutch-grown bulbs `Apple Blossom' and `Red Lion'. `Sun Dance' was the quickest flower and `Red Lion' the slowest. The effects of the planting medium on days to market and flowering were variable and no medium appeared to be the best for this criterion. `Summertime' and `Red Lion' produced longer leaves at flowering than `Apple Blossom' and `Sun Dance'. Three media that led to the production of the longest leaves, a desirable trait, were: Sunshine no. 4, Fafard 3-B, and Sunshine Post-Harvest. `Apple Blossom' was the tallest cultivar followed by `Sun Dance', `Red Lion', and `Summertime'. Effects of the planting medium on total plant height were variable. The overall plant quality ratings for use as potted plants ranged from 3.4 to 3.8 out of 4 for `Summertime', `Sun Dance', and `Red Lion'. `Apple Blossom' was rated 3.0 because it was tall and had short leaves. It would be suitable as a cut flower. Regardless of the planting medium used, `Apple Blossom' lost the greatest amount of old basal roots. Consequently, it produced many new basal roots. The planting medium had variable effects on old and new basal roots and secondary root growth, depending on the cultivar. Based on all the flowering criteria and the rooting responses, the best media for all cultivars as potted plants were Fafard 3-B and Sunshine Mix no. 4. Fafard no. 2 was best for cut-flower usage since it produced taller plants with a good root system.