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![](images/BESW-Nfield-marbushdet-21Dec04.JPG)
Early and completely 'shifted' B. swaseyi – was the same in both 2004 and 2005.
Among the very green background plants are B. trifoliolata.
Maroon Shift of Berberis swaseyi Winter Leaves
by Bob Harms
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A striking characteristic of most B. swaseyi bushes is their maroon winter leaf coloration. As noted by Correll & Johnston 1970 "leaflets ... turning a deep red in fall." Not noted, however, is that these same leaflets return to green with warm spring weather, starting in March.
![](images/BESW-grn2red-Xcut.JPG)
Leaflet cross section.
During the winter months these bushes are often easily identifiable at some distance, clearly contrasting with B. trifoliolata and most hybrid plants, which remain green.
![](images/S10-T4-bushcmp.JPG)
B. swaseyi (left) & B. trifoliolata
But great variation may be noted in the extent of this maroon shift. Not all leaflets are equally affected: some turn completely maroon, some only partially, generally at the outer edges. Some bushes seem unaffected. A comparison of these effects over two quite different winters (2004-5 and 2005-5) would seem to support the following variables:
- temperature: a hard freeze seems to be the trigger for the shift, and also a factor in the extent of the shift;
- moisture: 2004 had a 'wet' fall & winter; by contrast 2005 brought severe drought and a high percentage of leaflets turned bright red or yellow, then brown and were lost by late winter;
- exposure: bushes in deep shade generally did not exhibit this shift – but adjacent plants with the same exposure had differing degrees of color shift;
- maturation: recent fall leaves seemed to be unaffected;
![](images/BESW-sdcany-strongred.JPG) | ![](images/S15-8Dec04-grnlfs.JPG) |
Strongly maroon plant together with B. trifoliolata. | Unshaded B. swaseyi S15 remained green. |
Winter plants that were the same in both years. |
- genetics: plants that exhibited both extremes of the maroon shift — i.e., complete strong maroon coloration and virtually no effect at all — reacted the same way in both years.
For the most part winter leaves of the hybrids maintained the same green quality as B. trifoliolata, but a few plants exhibited a somewhat limited maroon shift.
![](images/BESxT-BETR-19Feb-lfs.JPG) | ![](images/S16-H9-21Dec-redlfcmp.JPG) |
B. trifoliolata & hybrid | Hybrid H9 and B. swaseyi S16 |
Variation in winter hybrid leaves — compared with B. trifoliolata & B. swaseyi. |
The maroon shift should not be confused with the redness of new leaves, typical of both species in late summer and fall. These are a bit more red than maroon.
![](images/BESW-7Nov-newrdlfs.JPG) | ![](images/BETR-newredlf-26Nov04.JPG) |
B. swaseyi | B. trifoliolata |
New leaves resulting from fall rains, Nov. 2004. |
Fall/winter leaflets of both species often turn brighter red or yellow prior to falling.
![](images/BESW-27Dec-yelredlfs-A.JPG) | ![](images/BETR-redyellfs-11Dec04-A.JPG) |
B. swaseyi | B. trifoliolata |
Leaflets prior to abscission. |