annapi wrote:Actually, this is the first year my coneflowers bloomed, and half of them, on the southern side are dark pink, and the other side is very light pink. My soil in Nevada is very alkaline but I do mulch a lot. Anymore suggestions??
Echinacea prefer slightly acidic soil so it is possible that the color variation is from the alkaline soil. It also could be a hybrid that is just not a good hybrid.
Try getting
Miracle Gro for Acid Loving Plants to use as an interim solution. It is formerly known as "
MirAcid" and may help the coneflowers. Also buy some sphagnum peat and work it into the soil all around the plants. Both of those will add a little acidity, albeit not a lot.
The way to adjust soil pH is with
sulfur. It needs to be done a year before a planting and repeated as necessary. Adjusting after plants are established is a bit more difficult because the sulfur (& :. pH change) just does not migrate very far into the soil and getting it too close to the roots can burn them, resulting in dead plants.
Aluminum sulfate will acidify the soil but also adds salt(... a bad thing). It is fairly commonly used to make blue hydrangeas "blue" rather than pink. It is also a bit
safer to use since over applying it is a bit harder.
Over time(years), nitrogen fertilizer will acidify the soil also.
Pine needle mulch is a good mulch for them but it will not acidify the soil to any appreciable degree. Working peat into the soil around the plants will do better but it too is not going to make an appreciable change over the long run because it breaks down. ( Breaking down process is
a good thing as it makes the soil more friable & rich but the pH change is soon lost as the soil will return to its natural level. )
No method is permanent but sulfur will last longer.
READ: https://hubcap.clemson.edu/~blpprt/lowerpH.html
As someone else wisely mentioned,
the first step is getting the soil tested. The County Extension service usually does that (for free too) but there are kits you can get to do it yourself.
(Call the Ext. Service and ask them what to do. They know the soil and help small gardeners as well as big farmers,

.)
Have Fun!
PS
Cottonseed Meal is an organic fertilizer that is acidic and has slow release of nutrients. The 'MirAcid' foliar feeding will act faster but in the long run using cottonseed meal for fertilization that will lower pH is probably the better way to go. It certainly is easier than once a week foliar feeding,

.