Consistent watering is necessary for Larkspur to bloom well and grow healthy all season long. Their large hollow stems will get floppy and topple over if they are not given enough moisture. Larkspurs are not the type of perennial that becomes drought tolerant as it matures. Insufficient watering at any stage of the plant's life will kill it. Using techniques like drip irrigation and mulching will make the watering process much easier and more efficient for you.
How To Tell If Larkspur Needs Watering
Larkspur will reduce the number and size of flowers as a first sign that it is not being watered sufficiently. Dry plants will direct any moisture uptake into the roots and foliage. The next sign is the drooping of foliage and any flower stems. Larkspur that are not watered enough are more liable to be attacked by powdery mildew. The disease does not kill Larkspur, but it will coat the leaves with an unpleasant powder, which can be transmitted to the rest of the plant. Infected foliage needs to be removed as soon as possible and thrown away or burned, not put in a compost pile.
How Often To Water larkspur
Larkspur needs at least 1-1½ inches of water during the week when it is newly planted. The soil should never dry out completely around Larkspur, but it also needs to drain well to prevent root rot. The best way to keep the soil moist is to use organic mulch around the base of the plant. Organic compost, shredded leaves, or untreated grass clippings conserve soil moisture and will release nutrients as they break down over the season.
Always mulch the soil when it is wet to keep the mulch from acting like a sponge and absorbing all of the moisture from the soil. Water approximately 2-3 times a week to encourage the roots to grow deeper in the soil. The deeper they grow, the less likely they are to be bothered by short periods of dryness and heat.
Larkspur does not become more drought tolerant as it matures. Older plants will need the same amount of water as newly planted ones. Continue with longer watering sessions and replace the mulch as needed to retain soil moisture. Using a drip irrigation system or soaker hoses helps to get the moisture right where the plants need it the most, the roots. This type of watering also keeps the foliage dry, reducing risk of an attack by fungus or mildew. Mulches can cover drip irrigation hoses without reducing the performance.
Larkspur in a container will need daily monitoring for moisture, no matter what season it is. Smaller containers dry out much quicker than larger ones and may need checking twice a day in the hottest part of the summer. The potting soil should feel like a tightly wrung-out sponge at all times. Watering thoroughly until water comes out of the drainage holes is the best way to ensure that all of the soil is saturated.
Best Time To Water Larkspur
Water as early in the day as possible. The cool, damp condition of the early morning will help plants to absorb as much water as they need with little evaporation.
Larkspurs need watering from the time they emerge in the spring up to when the ground freezes in the fall. Even though the plant goes dormant for the winter, the root system needs a certain amount of moisture to stay alive. Only water when the temperature is above 45 degrees F in the fall and try to avoid wetting the foliage.
How to Water Larkspur
Step 1 - Keep Larkspur constantly moist during the growing season.
New plants and mature ones need the same amount of watering. They prefer 1 - 1½ inches of water during the week and will need supplemental watering if the natural rainfall is less.
Step 2 - Use drip irrigation or soaker hoses as much as possible.
These types of watering systems help to direct the water directly where it is needed with little evaporation. Watering long and deep will encourage deeper root growth that is able to tolerate a small amount of dry or hot weather.
Step 3 - Use a 2-3 inch layer of organic material for mulch.
Mulching helps to cool the soil and retain more moisture for longer periods. Using a decomposable mulch like straw, compost, or shredded leaves will also add some nutrients to the soil and support beneficial microorganisms as it breaks down.
Larkspur Watering Tips
- Larkspur appreciate even, constant moisture
- Mulching helps retain moisture in the soil
- Drip irrigation and soaker hoses efficiently get the water to the roots where the plant uses it
- Plants do not tolerate watering in temperatures below 40 F.
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Author Robbin Small - Published 8-22-2022