How Much Should I Water My Perennials?
Perennials need about an inch of water per week, but the exact amount will vary depending on factors such as soil type, plant age, local climate, and type of perennial. According to Constance Schmotzer at Pennsylvania State University, "The rule of thumb is to add one inch of water per week for established plants. Less frequent but deep watering encourages perennials to root deeply. Perennials that are said to tolerate drought are drought tolerant only after they have become established."
Soil type: Sandy soils drain quickly, while clay soils hold onto moisture. Sandy soils will need more frequent watering, while clay soils can be watered less often.
Plant age: Young perennials need more frequent watering to establish their root systems. Mature plants can typically tolerate drier conditions.
Local climate: Hot, dry climates will require more frequent watering than cool, moist climates.
Type of perennial: Some perennials, such as lavender and sedum, are drought-tolerant and can survive with infrequent watering. Other perennials, such as hostas and ligularia, are moisture-loving and need regular watering. To determine how much water your perennials need, check the soil moisture regularly. Insert your finger into the soil up to the second knuckle. If the soil is dry, it's time to water.
Drought-tolerant perennials: These perennials, such as lavender and sedum, can survive with infrequent watering. Water them deeply once a week, or less often during the winter months.
Moisture-loving perennials: These perennials, such as hostas and ligularia, need regular watering. Water them deeply two or three times a week, or more often during hot, dry weather.
Perennials with special needs: Some perennials, such as ferns and irises, have special watering needs. Be sure to research the specific needs of your plants to ensure that you are watering them correctly.
How Often Should I Water Perennials?
Perennials need to be watered every 7-10 days during the growing season, more often during hot summer months and less often in the fall and winter.
Signs that it's time to waterWilting: When perennials lack sufficient moisture, their leaves and stems may appear limp or droopy. Leaf browning: In response to water deficiency, leaves may start to turn brown at the edges or even curl. Slowed growth: Drought-stressed perennials often exhibit slowed or stunted growth.
When Should I Water Perennials?
The best time to water perennials is in the early morning, just after sunrise. This allows the plants to absorb moisture before the day's heat sets in and reduces the risk of evaporation. Avoid watering in the evening, as this can lead to prolonged leaf wetness and create favorable conditions for fungal diseases.
Other factors to consider when watering perennialsWindy conditions: Avoid watering on windy days, as the water can drift away from the target area or evaporate quickly. Extreme heat: Avoid watering when the sun is scorching, as this can lead to rapid evaporation and ineffective moisture absorption. It's best to wait until the temperature cools down, typically in the early morning or late afternoon. Heavy rain: If rain is in the forecast, it's generally unnecessary to water your garden just before the rain arrives. Nature will take care of the watering for you. Plant growth cycles: Newly planted perennials may require more frequent watering to establish their root systems. During flowering and fruiting, perennials often demand more water to support these energy-intensive processes. In the fall and winter, as many perennials enter dormancy, their water requirements decrease.
Watering Tips from the Pros
Mulch is Your Best Friend
Mulch is a material that is spread over the soil to help retain moisture, suppress weeds, and improve soil quality. It is an essential tool for watering perennials effectively.
Mulch helps to retain moisture in the soil by:Reducing evaporation: Mulch forms a barrier between the soil and the sun and wind, which helps to reduce the rate of water evaporation from the soil surface. Regulating soil temperature: Mulch acts as an insulator, keeping the soil temperature cool in the summer and warm in the winter. This helps to create a more stable environment for plant roots, which can lead to better water absorption.
There are many different types of mulch that can be used for perennials. Some popular options include:Wood chips: Wood chips are a durable and attractive mulch that can help to suppress weeds and retain moisture. Straw: Straw is a lightweight and easy-to-spread mulch that is especially beneficial for perennials that are sensitive to harsh sun exposure. Compost: Compost is a nutrient-rich mulch that can help to improve soil quality and retain moisture.
When applying mulch, it is important to:Apply a 2-4-inch layer of mulch around your perennials. This depth will provide an effective moisture-retaining barrier and help to suppress weed growth. Leave a small gap between the mulch and the stems of your perennials. This will help to prevent excess moisture from accumulating around the base of the plant, which can lead to rot and diseases.
Water Where the Roots Are
To water perennials effectively, it's important to understand their root systems. Different types of perennials have different root depths, so it's important to know your plants.
Types of perennial root systemsFibrous roots: Many perennials, such as coreopsis and rudbeckia, have shallow, fibrous root systems that spread out horizontally near the surface. These roots are excellent at absorbing moisture and nutrients, so it's important to water them regularly. Taproots: Some perennials, such as delphiniums and baptisia, develop deep taproots. These roots can reach down into the soil to find moisture, so these plants can tolerate drought better than perennials with fibrous roots.
When watering perennials, it's important to focus on the root zone. This is the area around the base of the plant where the roots are located.Water at ground level. Avoid watering the foliage, as this can lead to fungal diseases and leaf scorch. Water deeply and less often. This will encourage deep root growth, which will help plants to withstand drought.
Check the Soil Before Watering
Testing the soil moisture before watering is essential for avoiding overwatering and underwatering. There are a few different ways to check the soil moisture:Finger test: Insert your index finger about an inch into the soil. If the soil feels dry at this depth, it's time to water. If it feels moist, there's no immediate need for watering. Soil moisture meter: Soil moisture meters provide a digital readout of moisture levels. They offer precise measurements and are particularly helpful for large gardens. Visual inspection: By observing the soil's appearance and texture, you can often gauge its moisture content. Dry, crumbly soil indicates a need for watering, while soggy, compacted soil suggests excess moisture.
Different soil types have different moisture-holding capacities. Sandy soil drains quickly and may require more frequent watering. Loamy soil retains moisture well, while clay soil can retain water for extended periods. It's important to adjust your watering schedule to account for the type of soil you have.
Water in the Morning
The best time to water perennials is in the morning. This is because the cooler temperatures help to prevent evaporation, so more of the water you apply will reach the roots. Additionally, morning watering helps to reduce the risk of fungal diseases, which thrive in moist conditions.
Watering in the evening is not recommended, as it can leave the leaves wet overnight and create conditions that are favorable for fungal diseases to develop. Additionally, watering during the heat of the day can lead to rapid evaporation, so the water may not have a chance to reach the roots before it evaporates.
Watering your perennials slowly is important for two reasons:
- It allows the water to penetrate the soil deeply, ensuring that the roots receive the moisture they need.
- It helps to prevent water runoff, which is wasteful and can harm the environment.
Methods for slow and steady wateringSoaker hose: A soaker hose is a long, perforated hose that releases water directly at the base of plants. It is a great way to water perennials with shallow roots, as it delivers water slowly and evenly. Flow control nozzle: Attaching a flow control nozzle to your hose allows you to adjust the water flow rate. This is helpful for watering different areas of your garden without causing runoff.
Make Every Drop Count
Efficient watering techniquesHand watering: Provides you with the opportunity for personalized care and precise attention to your perennials' needs. Watering cans: Provide precise control over water distribution. Their gentle flow is particularly beneficial for young or delicate perennials. Hoses with watering wands: Extend your reach and offer versatile flow options. They're ideal for reaching plants in the middle of garden beds. Nozzle with adjustable flow: Offers control over the intensity and range of water, allowing for customized watering. Soaker hoses and drip irrigation systems These efficient watering systems offer precise moisture delivery to your perennials, ensuring they receive the right amount of water at the root zone. Soaker hoses: Designed to ooze water slowly along their length. They are placed on the ground and can be easily arranged to water multiple plants simultaneously. The slow, even flow of water helps prevent runoff and ensures that the soil around the roots is consistently moist. Drip irrigation: Consist of tubing and emitters that deliver water directly to the base of each plant. They are highly efficient, reducing water waste, and are particularly useful in conserving water while keeping your perennials healthy. Smart irrigation controllers: Smart irrigation controllers can further help you conserve water by automatically adjusting your watering schedule based on weather conditions and soil moisture levels. Oscillating and impact sprinklers Sprinkler systems, whether oscillating or impact, are efficient choices for covering larger garden areas. Both oscillating and impact sprinklers are designed to distribute water evenly. While their efficiency may vary, they are generally more water-efficient than hand watering. Oscillating sprinklers: Move back and forth, providing even coverage across a rectangular area. They are suitable for many garden layouts but may not be the most water-efficient option.
Overwatering is one of the most common causes of death for perennials. It can lead to root rot, fungal diseases, and nutrient leaching.
Signs of overwateringWaterlogged soil: If the soil around your perennials is constantly soggy, this is a clear sign of overwatering. To avoid this, make sure your garden has proper drainage. Yellowing or wilting leaves: Yellowing or wilting leaves can be a sign of root suffocation due to excessive moisture. They may also develop a moldy appearance. Pest attraction: Excess moisture can attract pests such as slugs and snails, which thrive in damp conditions. These pests can harm your perennials.
How to avoid overwateringObserve your perennials regularly: Pay attention to the appearance and behavior of your perennials to assess their water needs. Factors such as the weather, soil type, and plant maturity can all affect how much water your plants need. Adjust your watering routine: Be flexible with your watering schedule and water when your plants need it, not on a set schedule. Water deeply and less often, so that the water reaches the roots and encourages deep root growth. Avoid watering in the evening, as this can promote fungal diseases. Mulch around your plants: Mulching around your perennials with a layer of organic material, such as bark chips or wood shavings, can help to retain moisture and suppress weeds. This can help to reduce the frequency of watering needed.