|I have a Sonora Rudebeckia for 2 years now and the plant is not showing very vigourous growth. It is watered and fertilized regularly it is also mulched with lawn clippings. It gets almost a full day of sun. Is this plant hardy to zone 4? If I could get more info on this plant it would be great.|Answer from NGA
August 27, 2006
|This is a named variety of Rudbeckia hirta. It is considered perennial and is winter hardy to zone 3. However, it blooms so much that after about two years it seems to exhaust itself. If you allow it to reseed, you should have an ongoing supply of young vigorous plants each year. It grows best in full sun with evenly moist yet well drained soil, using an organic mulch will help the soil stay more evenly moist. A topdressing each spring with compost and/or a general purpose granular or slow release fertilizer should be fine. Enjoy!
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