Geraniums not only supply a plethora of colour, but a continuum of old world charm to the much storied history of Government House.
The secret to growing good Geraniums is sunshine and the more they receive the more flowers they produce. In our heated greenhouse where they receive constant sun, they bloom all year. But even when strategically placed inside the house, they will only bloom from March through October when days lengthen and shorten respectively. For this reason, the plants must be rejuvenated, placing them back into the greenhouse to be utilized at a later date. Geraniums prefer cool night temperatures in the 50s/10°C and days around 70°F/21°C. Soil should be allowed to become moderately dry between good thorough waterings. Using an all purpose soluble fertilizer such as 20-20-20, feeding them every two weeks from March through October and once a month during winter should satisfy their needs.
Contrary to conventional wisdom, we have always dug up our outdoor Geraniums around the first frost in preparation for potting indoors. Only the most healthy and disease free are selected. Traditional teaching tells us due to root loss during this process, the resulting plants are very much inferior. I can tell you that this is seldom the case. We have grown some show stopping gigantic leafed specimens and cuttings, utilizing such a technique. On an overcast day, we simply dig up selected plants with as much root ball as possible. We bring the plants inside, wash the garden soil from their roots and plant in appropriate size pots. I like to incorporate a 14-14-14 slow release granular fertilizer into the artificial soil mix used at this stage and water thoroughly. The slow release fertilizer coupled with the once a month feeding will provide the nutrients required to produce strong, vigorous plants. Before they are placed in a well lit area of the greenhouse, they are cut back by about half just above a leaf mode. When new growth reaches 4 to 5 inches in length, cuttings at least 2 inches long can be taken and stuck in small water soaked Oasis cubes. These cubes must be kept moist and in 3 or 4 weeks you will notice healthy white roots protrude through the bottom of the cube, a sign they are ready for planting.
A viable alternative to cuttings is starting Geraniums from seed. If started in early February, plants can be in bloom for late June. I have always started a small amount of Geranium seed each year at Government House. Using a commercial seeding mix, cover seeds with ¼ inch of fine soil or vermiculite and soak with warm water. Cover pots or flats with clear plastic and if possible, place them on a heating pad. If bottom heat is not an option, then a constant air temperature of 85°F/29°C should be maintained to create a 75°F/24°C soil temperature required for germination. After seedlings have germinated, a night temperature of 60°F/15°C should help develop seedlings nicely. When seedlings develop their first set of true leaves, they can be transplanted to 3 ½ or 4 inch pots.
Geraniums continue to be the most utilized plant throughout the year at Government House.