I planted a bunch of ivy to cover a concrete wall. It’s robust and healthy, but not clinging to the wall at all. It doesn’t appear to have any aerial roots at all. How long does it take to start climbing? is there anyway to encourage it to climb?
What you have there is the very common English Ivy (Hedera helix). Looking at the leaves, there seems to be a whiteness to the veins, so it may be a variety known as Baltic Ivy.
From the picture, it seems the ivy is healthy and well established. According to the American Ivy Society website (www.ivy.org/faq-home.htm), in their FAQ section, “how does ivy stick to the wall anyway”, the writer states that the Ivy Society believes in the old adage: “the first year it sleeps, the second year it creeps, the third year it leaps.” It just may be that it will take three years before this ivy really begins to climb. It may be putting all its energy into developing a good root system. Additionally, there are good pruning tips in the aforementioned FAQ (about pruning back long leaders to encourage rooting/sprouting).
Although the ivy may be exactly what you want to cover the concrete wall, you should be aware that the attaching hairs are capable of crumbling mortar. As well, it is potentially invasive, particularly if planted near a natural area, such as a ravine.