Abstract:
Several studies of herbaceous perennials have addressed the effects of
environmental factors during and after production, inherent cold hardiness, and
post-harvest handling procedures to enhance flowering and growth during
establishment. The regrowth of both woody and herbaceous forage plants
following establishment is reported to be directly related to reserve-nitrogen
content. Plants with higher nitrogen reserves grow sooner and produce more
growth than plants with low reserves.
The first objective in my study, carried out in the greenhouse and outdoors,
was to identify any relationship between initial plant size and the regrowth of
fourteen herbaceous perennials from five nursery sources. Of the varieties
analyzed, six showed differences in growth between nurseries when grown
outdoors, but it appears this was not due to their initial plant size.
The second objective was to determine whether reserve nitrogen (N) content
or the level of reserved total nonstructural carbohydrates (TNC) had an effect on
regrowth. In this greenhouse experiment, six out of nine varieties that had higher
levels of reserve N per plant tended to grow more. In contrast, five varieties
showed more growth with higher levels of reserve TNC per plant. This suggests
that reserve nitrogen may have more effect than carbohydrates on the regrowth of
perennial plants during establishment.
The third objective was to determine the timing of N uptake from soil applied
N after establishment. For this greenhouse experiment, double-labeled
depleted ammonium nitrate was applied to plants of Astilbe chinensis 'Pumila' 10 d
after they were transplanted in the greenhouse. The uptake started soon after the
application; 40% of the ¹⁵N was detected by Day 10, and then leveled off. This
study suggests that herbaceous and woody perennials are similar in their
requirement for reserve N for new growth.
In general, the growth of herbaceous perennials appeared to be related to
reserve N content rather than to initial plant size or levels of stored carbohydrates.
However, this is preliminary study, and more studies are necessary for further
investigation.
regrowth of
perennial plants during establishment.
