Planting Dianthus (Caryophyllaceae) the correct way is step 1 to ensure you have healthy beautiful looking plants for years to come. It isn't difficult to do correctly, but following a few easy steps at the beginning will ensure you don't run into problems in the future.
What You Need To Plant Dianthus
You will want to get a shovel or gardening spade, compost or manure to mix in with the native soil (or any nutrient rich additives), and a water source like a hose, watering can or a large 5 gallon bucket. Carnations don't require any special tools or materials to plant compared to other outdoor plants.
Where to Plant Dianthus
Dianthus prefer locations that receive full sun to partial sun. Any location with at least 6 hours of direct sunlight per day. The plants like fertile soil that is nutrient rich but drains well. If the soil does not drain well, and the roots constantly stay wet, the roots will rot and the plant will eventually die. Carnations like alkaline soil if possible, but can adapt somewhat to more acidic conditions as long as it isn't too far on the other end of the spectrum. Plant as deep as the it was growing in the pot it comes in. If you plant too deep, water will have trouble draining away from the plant. If anything, plant slightly higher than the native ground around the plant.
Carnations should be planted around 12-18 inches apart, center on center in most cases. To determine exactly how wide, take the width of the mature size of the plant, and make sure the plants are spaced out at least that much. So if the mature plant spread is 12 inches wide, plant those at least 12 inches away when measuring the center of the holes you dig for each plant. The same rules go for planting away from structures like rocks, buildings and other plants.
Steps To Planting Dianthus
Step 1 - pick the right location for the plant. If you choose to grow dianthus in a planter, then make sure you have a location to put the planter that gets enough sunlight each day.
Step 2 - dig a hole that is 2-3 times larger than the root ball of the plant. Try not to dig deeper than the height of the current root ball.
Step 3 - mix manure or compost in with the native soil from the hole you dug out.
Step 4 - place the plant into the new hole and push the excess dirt back in around the plant, packing the dirt down firmly, but not too hard.
Step 5 - water the plant so the soil is completely saturated all around the plant. It is important that you start the plant off with plenty of moisture to help get it established.
Tip: Never mulch around dianthus plants.
When to Plant Dianthus
You should wait until the danger of frost has passed before planting dianthus. We recommend planting dianthus in the spring if possible. However, you can plant carnations all through the summer and into fall until there is risk for a freeze overnight. We recommend not planting 2-3 weeks before the first anticipated frost.
Try to plant during a cloudy or overcast day if possible. Early morning or late evening is best too. That put the least amount of stress on the plant as it gets transplanted to its new location. It also helps the water not evaporate and prevents the roots from drying out before you have a chance of putting the plant into the ground.
If you do plan on planting during the hot summer months, you will need to keep a close eye on the plant and ensure it gets enough moisture. The leaves will typically start to droop if it needs more water.
It is possible to grow dianthus from dividing the plants, growing them from cutting or from seed. Once you have plants ready to go into the new location you have picked out, follow the same instructions listed above. The roots of dianthus aren't very deep, so it is easy to dig underneath plants already in the ground. When moving from one spot to another, be sure to leave enough space for the plants to grow.
Also, dianthus can spread by seed. So be sure to deadhead the plants each year to prevent unwanted plants from popping up in the garden.