{"id":2728,"date":"2019-08-02T00:04:16","date_gmt":"2019-08-02T07:04:16","guid":{"rendered":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-519\/"},"modified":"2023-08-08T11:58:22","modified_gmt":"2023-08-08T18:58:22","slug":"rusty-leaves-on-asters","status":"publish","type":"pal","link":"https:\/\/depts.washington.edu\/hortlib\/pal\/rusty-leaves-on-asters\/","title":{"rendered":"rusty leaves on Asters"},"content":{"rendered":"

Our Asters are green and getting ready to bloom but the<\/strong>
\nlower 8″ are “rusty” or burnt looking. Did our bark mulch hurt them? Too much<\/strong>
\nfertilizer? This is their third year in the same spot.<\/strong><\/p>\n

 <\/p>\n

There are quite a few potential causes of the rusty leaves you are
\nseeing. It might be entirely normal, as mature Asters (renamed Symphyotrichum) can start looking a bit ragged in late summer. It could be due to excessive heat,
\noverwatering (symptoms include yellowing and dropping of lower leaves),
\nor fertilizer burn (Asters are sensitive to soluble salts in chemical
\nfertilizers). It could be a fungal disease, rust, or Aster yellows, a
\ncommon disease caused by a microscopic organism (phytoplasma) and spread
\nfrom plant to plant by leafhoppers. With Aster yellows, you would notice
\na loss of green in the leaf veins, and yellowing of new leaves.
\nSometimes, infected outer leaves turn a rusty or reddish purple color. A
\ngood general practice to keep your Asters looking full and less leggy is
\nto cut them back by one-half to two-thirds when they have reached 12 to
\n16 inches in late spring\/early summer. (Source: The Well-Tended Perennial
\nGarden<\/em> by Tracy DiSabato-Aust, Timber Press, 1998).) Here are
\nlinks to resources which describe other possible causes of the leaf
\nproblem.<\/p>\n

Connecticut Agricultural Experiment Station<\/a><\/p>\n

Missouri Botanical Garden<\/a><\/p>\n

To determine the exact cause, it might be worth bringing a sample to a
\nMaster Gardener Clinic<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Our Asters are green and getting ready to bloom but the lower 8″ are “rusty” or burnt looking. Did our bark mulch hurt them? Too much fertilizer? This is their third year in the same spot.   There are quite a few potential causes of the rusty leaves you are seeing. It might be entirely normal, as mature Asters (renamed Symphyotrichum) can start looking a bit ragged in late summer. It could be due to excessive heat, overwatering (symptoms include…<\/p>\n

Continue reading rusty leaves on Asters<\/span><\/a><\/div>\n","protected":false},"author":4,"featured_media":0,"menu_order":0,"template":"","keyword":[296,297],"class_list":["post-2728","pal","type-pal","status-publish","hentry","keyword-perennials-care-and-maintenance","keyword-symphyotrichum"],"acf":[],"_links":{"self":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal\/2728"}],"collection":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/pal"}],"about":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/types\/pal"}],"author":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/users\/4"}],"wp:attachment":[{"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/media?parent=2728"}],"wp:term":[{"taxonomy":"keyword","embeddable":true,"href":"https:\/\/depts.washington.edu\/hortlib\/wp-json\/wp\/v2\/keyword?post=2728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}