Browning of the *lower* leaves seems to be a normal occurrence with some cultivars of clematis. It usually happens in the heat of the summer after blooming time. Current knowledge suggests there is little that can be done other than to make sure that the plant is well watered and has a thick layer of organic mulch around its base to conserve moisture. Just prune away the dead leaves and leave the vines alone. Many times the leaves can just be crushed and they will fall away. Another type of browning leaves happens when the plant, or part of the plant, has suffered from 'wilt' and that portion has died. In this case the brown leaves extend to the growing tip and the vine becomes very brittle, almost black, and the axil buds are also brown or black. It takes some experience to determine whether this portion is dead. If the tip is bent and it snaps off cleanly, it is dead. Prune this down to either a living branch, live leaf axil, or to the base. The plant may be dormant for a period, but if kept well watered and fed you should see new growth shoot either later the same year, or the following year.

matt I don't know, but leaves usually shrivel and dry up if too dry. I don't use moisture meter (they are not that reliable, unless you have a better quality one); if I have any doubts I just stick a bamboo skewer deep into pot to check for moisture. Just checked my plant, there is 1 leaf that is yellowing - I am quite sure it is just old and is going to dry up and fall off. There are 3 big branches/stems on my plant, mostly 'naked', with leaves just at the top. It is constantly in bloom - I got it in 2012 and it never stopped blooming yet. It really needs to be repotted (still in pot & soil I got it in!), and also pruned, since there is no branching at all, and is getting too tall. Here is photo of 1 yellow leaf, and top of one of the branches:

might have a lot to do with planting in july in FL ... how were they planted.. and how have you been watering them .. one thing for sure.. they are stressed ... and it must be severe stress .. if leaves turned yellow in 10 days ... take a hand trowel.. and find out if there is any moisture down 3 to 6 inches.. where the roots are ... both on the gob planted.. and in close surrounding soil ....if you are relying on lawn irrigation.. that is probably the problem ... in my MI... i dont plant ANYTHING in july or august... maybe pensicola is different ... how about a pic or two.. so we can see size.. color.. etc ... ken

A magnesium (Mg) deficiency would present across the entire foliage mass because Mg is a nutrient that is considered mobile in the plant. As such, it can be borrowed from other organs to supply what is needed for new growth. A zinc (Zn) deficiency, because it is considered immobile in the plant, must be present in the nutrient stream at adequate levels at all times. If it isn't, deficiencies show only in new leaves that grew after the Zn became deficient. Generally speaking, when a deficiency of the mobile nutrients (N, P, K, Mg) occurs, it is seen in all foliage, even though roots are first affected. The rest of the nutrients which are absorbed via the root pathway are considered to be immobile or mostly immobile (can't be 'borrowed' to provide the building blocks for new growth). A simple analogy would be, leaves and fruit are having a tug of war to see which one gets the lion's share of food and nutrients. Since we know the pull of unripened fruit is always stronger than foliage (fruit is a more powerful energy sink than leaves), fruit will win every time. When fruit ripens, it's loses it's pulling power, which frees up food and nutrients that allow the leaves to recover to their normal color. I'm not sure what you meant by, "That happens when the trees aren't getting enough potassium and open". FWIW, most hobby growers end up shooting themselves in the foot when they think they have identified 'a nutritional deficiency' and move to treat it by adding an element or compound aimed specifically at correcting a deficiency of individual nutrients. The reasons for the shot in the foot are several. 1) Deficiencies are very often misidentified; or, 2) there might not actually be a physical deficiency of the nutrient the grower thinks (s)he identified as there could be another antagonistic nutrient, available in excess, in play, example: too much Ca limits Mg uptake - too much P limits uptake of K, Ca, Fe, Cu, Z, ....... ; or, 3) a nutrient could be acting as a synergist, example: an excess of K can cause an increase in the uptake of Mn and Fe, causing a toxicity of all three nutrients which would be read as a deficiency of who knows what; or 4) the deficiency could be culturally caused, example: in saturated soils, low oxygen levels cause Fe (iron) and Mn (manganese) to become electron acceptors. This leads to the precipitation of both, even though these elements might be present in soils at normally adequate levels, and the plant’s inability to assimilate them. Soggy soils also make uptake of Ca difficult or impossible. Al