Chrysanthemum flowers, which is used in herbal drinks and mixed in tea, such as pu’er, are quite often loaded with insecticides and preservatives. I do not recommend using them unless it’s tested outside of China for food safety. It has a pleasant taste and I do think it’s a shame that safer ones are not widely available.
As for the problem in tea, it is not an issue that affects products only of Mainland China, but rather all tea producing countries. Generally premium products are less affected than lower price ones. However, that is not to say all better teas are safe from it. For example, some major harvest of better sencha from Fukuoka was all tested for over dose of pesticides a few years ago. Some high price Longjing of some reputable origins in Hangzhou were found containing lead from environmental pollution.
Travel, logistics and communication have now been the most convenient and affordable ever in human history. Many think that buying directly from source is easy. Many importers are competing for time and price. They missed out on the important role of quality control.
On the other end, the pressure for profit and meeting market demands is high on the production side. When the world continues to glorify wealth and materialism, and in a country which religions and traditional ethics were totally destroyed, you have to rely on science to find out which producers deliver safe teas and which do not. Testing in properly qualified labs is a cost that is manageable in productions and purchases of a few hundred kilos, let alone medium priced ones. I think the merchants in your country have skipped some procedures.
