Posts: 1
Threads: 0
Joined: Jun 2009
06-17-2009, 07:26 AM
Re: (0...)
I notice that after some of my plants bloom the foilage gets a bit silvery/brown looking. Do I have fungus on them or do I just trim them back and see if they will rebloom? Also my iris did not bloom well this year. They don't look well; The leaves are streaked with brown and they seem to look like they are dying back. Could it be overcrowding or some type of rot? Thanks
Posts: 182
Threads: 0
Joined: Mar 2006
Iris, as well as gladioli, cyclamen, and members of the tomato and melon families, can be susceptible to fusarium wilt. The plants may look wilted or stunted, and eventually the leaves start turning yellow and fall off. Then the bulb rots. To see if you have fusarium wilt, slice a stem lengthwise. If there's some red crud visible in the plant tissues, then fusarium wilt may be the cause of your problems. If this is the case, then you'll have to remove and destroy the infected plants, and replant the area with fusarium-resistant cultivars. :-(
The fusarium bacteria multiplies best in cool, wet soil. The bacteria infect the vascular system of the plant, reducing the plant's ability to take up water, so the effects of fusarium wilt often are not noticed until the weather warms up and dries out in the late spring/early summer. This bacteria can exist in your garden soil for over 20 years, even if no host plants are available! Your best defenses against fusarium wilt in a perennial garden are to avoid over watering, especially in the springtime, and to avoid over fertilizing. Keep your garden tools clean, and disinfect them after working in an area infected with fusarium wilt (better yet, use two sets of tools if possible -- one set for the infected area, and the other for uninfected areas). In a vegetable garden, a long-period crop rotation (5-years) is recommended.
The great thing about gardening is that you always get a chance to start over!