There are two different groups of Herbs known as Geraniums.

Geraniums: The herbs we typically call Geraniums are not actually geraniums at all. They are members of the genus Pelargonium, formerly classified in the Cranesbill genus. They are commonly grown as an indoor and outdoor potted herb and are, actually, what we would receive from our local garden shop or greenhouse when purchasing Geraniums. The Pelargonium is subtropical in origin and typically planted as an annual because they are not winter-hardy. They are generally pot-grown so our Geraniums may be taken inside for winter.

Geraniums (Pelargonium) are available in many popular types that fit into one of the following groups:

Geranium or true Geraniums are frequently described as “hardy” or perennial geraniums. Members of the genus Geranium are winter hardy outdoor plants. They are good for use as perennial geranium borders and are often grown as much for their showy foliage as for the enjoyment of their symmetrically shaped flowers.
Pelargonium geraniums make attractive houseplants- Members of the genus Pelargonium, formerly classified in the Cranesbill genus. They are commonly grown as an indoor and outdoor potted herbs and are, actually, what we would receive from our local garden shop or greenhouse when purchasing Geraniums.

Zonal Geraniums, better known as common garden Geraniums, are usually sold as bedding plants. The leaves generally have a dark zoned pattern, tri-colored or silver leaves, leaves with bands or zones of red or white, or other distinctive markings. They display big, attractive flower heads that bloom in a variety of basic colors that may have single or double petals. Colors range from burgundy across the spectrum to white.
Scented Geraniums are smaller and less showy with flowers that are usually smaller and sparser than the annual Pelargonium or true perennial Geraniums. They are prized as potted herbs for a plethora of strong scents from the deeply-lobed, soft-textured leaves from which oils are emitted when the leaves are rubbed or crushed. Scents such as citrus, apple, rose, peppermint, nutmeg and even chocolate are common in the various types of the scented geranium.
Ivy Geranium or Trailing Geraniums have leaves that grow in a trailing habit like ivy foliage that will tolerate a fair amount of shade. This makes them a perfect herb for hanging baskets, outdoor shaded planters and window boxes. The flower color range a wide variety of colors from light to dark.
Regal or Martha Washington Geraniums grow up to 4 feet tall and do well in shade. Large showy flowers in many vivid colors make these geraniums very enjoyable. They are more often sold as indoor plants because they are not as heat tolerant as other geraniums. Other names for this group of geraniums include pansy, fancy or hothouse geraniums. They are usually propagated from geranium cuttings.
Mosquito Geraniums are plants developed by introducing a gene from Citronella grass into a scented Pelargonium species. When rubbed or crushed, these geraniums release the citronella oil, which is said to repel mosquitoes.

Best growing Zones in which to grow geraniums:

USDA Growing Zone: 4 and higher
Plant Type: Perennial

Best Soil type soil Type for growing geraniums:

Well-drained silty loam - with 2.5% organic matter or higher

Propagation of Geraniums:

Geraniums can be over wintered by taking cuttings from plants in early fall, before the first killing frost. Some geraniums do not propagate easily from cuttings although all can be stored as bare root plants in a cool dry location, such as a cool porch or basement, to be replanted in the spring.
Propagate geraniums from cuttings by filling sterilized pots 3 - 4 inches deep with pre-moistened, but not soaked, planting medium. The rooting medium can include coarse sand, perlite, or an even mixture of both. The safest choice is always one of the sterilized commercial rooting soil mixes which are available from a variety of sources.
1. Cut off shoot tips 3 to 5 inches in length. Remove the leaves from the lower part of the stem.
2. Dip the bottom of each cutting into a good rooting hormone, being sure to cover one or two of the points where you have removed a leaf.
3. With a pencil poke a hole into the moistened rooting soil in the pots and then insert the cuttings to a depth of 1-1/4 to 1-1/2 inches into the hole.
4. Firm the medium around the base of the cuttings to ensure good soil contact.
5. Cover the Geranium cutting with a plastic cover; a large zip lock works well. This provides the geranium cutting with its own private "greenhouse" in which to develop a strong root system.
6. Place the geranium with its cover in a warm location that receives bright, but indirect light. The bag will usually show moisture condensation on the inside. Remove the bag or open the top every few days to guard against heat buildup and excessive surface moisture on the geranium.

Growing geraniums indoors:

Pelargonium geraniums make attractive houseplants. They can be grown indoors for their ornamental value, as well as to maintain them for re-use in the landscape the following spring. They do best in full sunlight indoors but tolerate moderate light. Indoor temperatures that average 65 to 70°F during the day and around 55°F at night are considered optimal. Avoid locating them in extremely cold, hot or drafty areas.
Geraniums prefer a free draining potting soil for houseplants containing 2.5% organic matter or higher. Good drainage is essential. Allow the soil to become moderately dry between watering, and make sure there are drainage holes in the bottom of each container. Fertilize monthly from March through October. Use one tablespoon of 20-20-20 fertilizer, or two tablespoons of a 10-10-10 fertilizer per gallon of water or a similar formula. If in a low-light area, reduce the rate of fertilization accordingly.

Growing Geraniums in your outdoor herb garden:

Geraniums should not be planted outdoors until all danger of frost is past. Pelargonium geraniums enjoy a long growing season and enhance landscaping when planted directly in the ground, in hanging baskets, or in containers on decks, patios or entrances.
Geranium plants tend to break and wilt in windy locations so protection from strong winds is recommended.
Actively growing geraniums are heavy feeders. The loamy soil should be well drained and contain organic matter of 2.5% or higher. Add compost to your herb garden soil to give the Geraniums a boost.

Fertilizer: Fertilize with a balanced, water-soluble fertilizer such as 20-20-20 applied weekly. You can also one pound of a 10-20-10 dry fertilizer per 100 square feet. Incorporate the fertilizer into the soil, taking care not to dig so deeply as to damage the roots. Keep the fertilizer off the foliage and flowers.
Water: Be sure to water the plants regularly when it does not rain. Check containers regularly during hot summer weather. Simply poke a finger into the soil. If it is dry two inches down or more, it is time to water.
Grooming: Keep your plants looking their best by deadheading to promote new blooms and by removing dried or discolored leaves. Your geraniums will reward you by looking great all season.

Growing Geraniums can be enjoyed in a variety of surroundings.

Light requirements of Growing Geraniums: Nothing loves sunlight and warm temperatures as much as geraniums! They grow best when receiving at least 6 to 8 hours of full sun per day. When geraniums receive less light per day than full sun, they will flower proportionately less in direct proportion to the amount of light the plants receive. When temperatures reach 90 degrees F or above. In this case, it would be best to provide shade for your Geranium plant.