Rotary Botanical Gardens - Hort Blog: Nasturtiums

Today was a bit warmer and a beautiful sunny day. The afternoon high temperature was around 10 degrees F which is a huge improvement over previous days. The warm up over the coming days will allow us to get back out in the gardens for the take down of the expansive Holiday Lights Show (HLS). We'll also continue our pruning efforts that were started by Pat and Urban at the end of 2013. We had some nice volunteer assistance today. Pat worked on some painting and other indoor projects including preparing other items for repainting. He also headed out in the gardens for more lights retrieval where possible. Bill was in later and processed the lights that Pat had accumulated. Patrea and Dr. Gredler were in for priming duties and painting respectively. I saw Jumbo Jim this morning and we talked about the 2014 veggies and edibles that we'll be using. It's always nice to "talk shop" with Jim who is heavily involved over at the Rock County Farm & Community Garden and brings RECAPPER volunteers to the gardens frequently. Maury ran some errands for us and we also saw Mark S. and Big John.

This blog promotes one my favorite annuals, the nasturtium (Tropaeolum sp.) which a very easy to grow plant out in the full sun garden. I recommend letting kids plant nasturtium seeds as they are a slam dunk to grow and inspire our next generation of gardeners! They are also edible and nutritious. All of our "ornamental edible" collections in previous years have included nasturtiums which have edible leaves, stems, flowers and seeds (not sure about the roots...). Native to South America, this plant can thrive in tough soils as it does natively in the rocky conditions in the Andes. Nasturtiums don't need rich soil or fertilizer to thrive and in fact, if the soil is too rich, they will have very vigorous foliage growth at the expense of the blooms which will be more sparse. There are well over 100 cultivated varieties of nasturtiums with a wide range of flower colors and some variable flower forms. All your seed catalogs carry a wide range of varieties and the seed is inexpensive. Some varieties also feature "marbled" foliage which adds additional interest on these rounded leaves. Above is the 'Alaska Scarlet' variety at the Dubuque (IA) Botanical Garden which includes the marbled foliage. While nasturtiums will tolerate part sun, they tend to bloom less and can become stretched out and sparse. Look at how exquisite the blooms (1"-2" diameter) are when seen in close proximity (see below).

The marbled nasturtiums can be purchased with a specific color like the 'Alaska Salmon' seen above. There is also 'Alaska Scarlet' (top photo), 'Alaska Gold' and the 'Alaska Mixed' with all three flower shades. Note in the three photos below that no leaf is the same and maximum solar exposure results in better variegation. Nasturtiums have a peppery taste and have long been used to spice up a salad or sandwich. Their value as an edible garnish is apparent as well. It is certainly an acquired taste for some and should be sampled by those new to "nasturtium nibbling." The leaves are high in vitamin C and iron and have long been used as a natural antibiotic. There are countless herbal uses of this plant and in the mid 20th century, the dried seeds were ground and used as a pepper substitute and in herbal seasoning salts. See some of the photos further down to see the value of nasturtiums as an edger along a border or cascading over a wall. When you select varieties note that some are "clumpers" and some are "trailers". This designation will be important as you consider the space to be filled. I've seen them used in containers and hanging baskets but in those cases, they do require some light fertilization to keep the foliage looking good. Keep in mind that the trailing varieties will take up some real estate but can be sheared back severely and will bounce back readily. You really only need one seed per square foot for ample coverage by mid summer. Order some seeds for May planting!