I came across a great website the other day..google search
Rob's geraniums Rob has many and maybe you'll find something interesting on his site.

I attended a class on plant food. I don't remember the plant food number stuff (numbers are different for each brand), but I do remember that there are two kinds of plant food: regular plant food (encourages plant and leaf growth) and food just for encouraging the plant to bloom. Any plant food labled especially for booming will work. I have some geraniums that I mainly want for the large beautiful leaves. I have other geraniums for their blooms. I enjoy the options just by choosing the plant food! Hope this helps, enjoy your geraniums.

The first number on fertilizer is for Nitrogen, the second is Phosphorus and the third Potassium.

Fertilizers that are higher in Phosphorus than Nitrogen boost flowering.

Patience will work wonders also. My geraniums really took off flowering heavily in their third year in the garden. Til then, the flowering had been minimal and spotty. Like many perennials, the third year is the charm!

Kate

I find Rozanne (Roxanne) to be far superior to anything else It blooms heavily for me from June to October. But it's blue.

You might just try some other varieties until you find what works in your spot.

Kate makes a very good point - most perennials, hardy geraniums included, really do not come into their own until after a couple of seasons in the garden and full establishment. Three growing seasons is the rule of thumb.

A couple of other items to consider: most hardy geraniums prefer quite a lot of sun. And they like a modestly fertile, well draining but moisture retentive soil. Extra fertilization is generally not an issue. With decent soil, most perennials require minimal supplemental fertilization and unnecessary fertilizers tend to produce a lot of lush, lanky growth at the expense of flowering.

And regarding "plant food".......(and david, it is not my intention to single you out, but your comments did prompt this clarification :-)). Fertilizers are NOT plant food and any horticultural instructor that makes that claim doesn't know what they are taking about or is talking down to their audience. Plants manufacture their own food through the process of photosynthesis, converting sunlight, water and nutrients they draw from the soil into the sugars and proteins ncessary for healthy plant growth. All fertilizers are intended to do is to supplement basic plant nutrients that may be lacking or deficient in the soil. Unnecessary fertilization is counterproductive to good plant growth, contrary to what manufacturers like MiracleGro would have you believe. It encourages a lot of rapid, lush growth that is vulnerable to diseases and insects and increases the plants' demand for water and often at the expense of good flowering. If one takes time to improve or amend soil conditions properly, incorporating organic matter like compost into the soil or used a a mulch, there is very little need to ever add any other fertilizers. Geraniums tend not have heavy nutrient demands anyway and tend to prefer a relatively lean soil, as long as drainage is good and even moisture is available.