Agastache nepetoides
🍃leaf (5)
🌸flower (5)

Agastache nepetoides

Yellow giant-hyssop · Catnip giant-hyssop

Tier 1 Difficulty: medium Water: low Light: full_sun
Water every
7 days
Temperature
5–35 °C
Soil pH
6–7
Hardiness
Zone 4–9
Click count
141
Observations
65

Description

Source: leafsnap

Agastache nepetoides, commonly known as yellow giant hyssop, is a perennial flowering plant native to the central and eastern United States and Canada. It is a member of the Lamiaceae (mint) family.

Care Guide

💧 Water Every week

The yellow giant hyssop is originally from temperate regions and thrives with consistent hydration. It prefers moderate moisture levels, so watering it weekly is ideal. It's best planted in well-draining soil that can still retain some moisture. Commonly found in gardens, this plant benefits from natural rainfall, which helps enhance its foliage during the growing season.

Suggested frequency: Every week
FAQ
How should I water my Yellow giant hyssop?

To properly water the Yellow giant hyssop, it is recommended to use filtered water at room temperature. Tap water may contain harmful particles, so filtered water is preferred. The plant is accustomed to warm environments, so using cold water should be avoided to prevent shock. Additionally, overhead watering can cause issues with the foliage, so it is best to water the plant by applying filtered room temperature water directly to the soil. It is important to thoroughly soak the soil as this helps to moisten the roots and enable them to spread and collect nutrients effectively.

What should I do if I give my Yellow giant hyssop too much water or not enough water?

Both overwatering and underwatering can harm the health of your Yellow giant hyssop, but overwatering is more common. If the plant gets too much water, its stems and leaves may wilt and turn yellow. Overwatering for a long time can also cause diseases like root rot, mold, and mildew, which can kill the plant. Underwatering is less common for this plant since it can tolerate drought. However, it's still possible and can cause the leaves to become brittle and brown. It's important to notice signs of overwatering early. Some diseases caused by overwatering, like root rot, may be irreversible if you wait too long. Reduce watering immediately if you see signs of overwatering, and check the soil drainage. If the soil doesn't drain well, replace it with a loose, well-draining potting mix. If you notice signs of underwatering, simply water more regularly until the signs go away.

How often do I need to give water to my Yellow giant hyssop plant?

If your Yellow giant hyssop is in a pot, you can check if it needs water by sticking your finger into the soil. If the top two to three inches of soil feel dry, it's time to water. If you have Yellow giant hyssop planted in the ground outdoors, you can use a similar method to test the soil. When the first few inches of soil are dry, it's time to water. Usually, during spring and early fall, you'll need to water this plant about once a week. But during hot weather, you may need to water twice a week or more. However, mature and well-established Yellow giant hyssop plants can tolerate drought well.

How much water does my Yellow giant hyssop plant need?

To properly water your Yellow giant hyssop, it is important to be generous with the amount of water you give. Make sure the first two to three inches of soil are dry before watering, and then water the plant thoroughly, ensuring that the soil is completely soaked. You should add enough water that it flows out through the drainage holes at the bottom of the pot. If you don't see any excess water draining, it's likely that you haven't given enough water. However, be careful not to let water accumulate in the soil, as this can be harmful to the plant. On the other hand, if water isn't draining through the pot, it could mean that the soil doesn't drain well, which is not good for the plant's health. If the plant is outside, it will generally only need about 1 inch of rain per week.

How do I water my Yellow giant hyssop at different stages of growth?

The water needs of the Yellow giant hyssop can vary depending on its growth stages. When the plant is in its early years or has recently been transplanted, it requires more water than usual. During these stages, the Yellow giant hyssop focuses on developing new roots that support future growth. These roots perform best with slightly more moisture. As the plant matures over a few seasons, it will require less water. Another stage that may require increased watering is during the bloom period, as the flower development uses a significant amount of moisture.

☀️ Light Full sun

Yellow giant hyssop grows best in places that receive plenty of sunlight each day. This encourages optimal growth and peak vigor. While it can tolerate some shade, a reduction in light may reduce its vigor. Its native habitat has abundant sun, indicating it is naturally adapted to those conditions. Either extreme of light exposure can stress the plant and affect its overall health.

Ideal: Full sun
FAQ
What are the sunlight requirements for Yellow Giant Hyssop?

Yellow Giant Hyssop requires full sun, which means it needs more than 6 hours of sunlight daily for optimal growth. It can also grow in partial sun, receiving about 3-6 hours of sunlight. It's important to note that while the plant thrives under abundant daily illumination, some degree of shade is tolerable. Nonetheless, less light may impact the plant's vigor negatively. Observing how sunlight moves through your garden and choosing spots with a perfect balance of light and shade ensures the plant's happiness and health.

How does artificial lighting support Yellow Giant Hyssop growth indoors?

Indoor Yellow Giant Hyssop plants require adequate lighting for optimal growth, especially when natural sunlight is insufficient. Artificial lights, such as LEDs, are beneficial as they can be customized to provide specific wavelengths necessary for the plant. Full sun plants need 30-50W/sq ft, partial sun plants need 20-30W/sq ft, and full shade plants need 10-20W/sq ft of artificial light. The light source should be placed 12-36 inches above the plant to mimic natural sunlight and should be kept on for 8-12 hours per day to promote faster, healthier growth.

What are the symptoms of insufficient light in Yellow Giant Hyssop?

Symptoms of insufficient light in Yellow Giant Hyssop include smaller new leaves, leggy or sparse growth, faster leaf drop, slower or no new growth, and lighter-colored new leaves. These signs indicate that the plant is not receiving adequate sunlight, leading to reduced chlorophyll and essential nutrients. Moreover, symptoms like chlorosis, sunscald, leaf curling, wilting, and leaf scorching could signify light-related stress, either due to low or excessive sunlight exposure. Recognizing these symptoms is crucial for adjusting care practices to improve plant health.

How can I improve the growth of Yellow Giant Hyssop with insufficient sunlight?

Improving growth for Yellow Giant Hyssop with insufficient light involves several strategies. Indoors, gradually moving the plant to sunnier locations or using artificial light sources, such as desk lamps or professional grow lights for at least 8 hours daily, can significantly boost light exposure. For outdoor plants, a gradual relocation towards sunnier spots prevents sunburn, while strategic pruning of obstructions like trees can increase sunlight access. Additionally, for ground-planted specimens, transplanting during the dormant period to a brighter location with good drainage enhances growth. It’s vital to act on increasing light exposure cautiously to ensure new growth is healthy.

🌡️ Temperature 5–35°C

Yellow giant hyssop is native to temperate regions and does well in temperatures from 41 to 95 °F (5 to 35 ℃). It might need adjustments during extreme seasonal conditions, particularly in periods of severe cold or heat waves.

Ideal temperature: 5–35°C
FAQ
What is the native climate for Yellow giant hyssop?

Yellow giant hyssop, botanically known as Agastache nepetoides, is native to temperate climates. It thrives in temperatures ranging from 5 to 35 °C (41 to 95 °F). Despite its strong resistance to cold, adjustments may be necessary under extreme weather conditions, particularly during severe cold or heat waves.

How does Yellow giant hyssop handle cold weather?

Yellow giant hyssop has a strong resistance to cold and generally does not require special frost protection measures during winter. However, if temperatures are expected to fall below -30°C, it’s important to protect the plant by covering it with materials like soil or straw. To prepare for winter, it’s recommended to water the plant abundantly before the first freeze of autumn, ensuring the soil remains moist and enters a frozen state. This preparation helps to prevent drought and water scarcity for the plant during the winter and early spring times.

What should I do if the temperature drops below -25°C for Yellow giant hyssop?

Although Yellow giant hyssop is cold-tolerant, temperatures below -25°C may not show immediate negative effects, but could lead to decreased sprouting or no sprouting in spring. If there has been exposure to such low temperatures, it's advisable to remove any parts of the plant that have failed to sprout during the spring as a remedial solution.

How should Yellow giant hyssop be cared for during high temperatures?

In high temperatures, particularly above 35°C, the Yellow giant hyssop needs extra care to prevent stress and damage. Signs of high-temperature stress include leaves becoming lighter, prone to curling, susceptibility to sunburn, and in severe cases, wilting or drying of the entire plant. To mitigate these effects, it's recommended to trim away sunburned and dried parts of the plant. Move it to a shaded location, especially away from the midday and afternoon sun, or use a shade cloth. Ensure the soil remains moist by watering the plant in the morning and evening.

💨 Humidity
Humidity:
🪴 Soil 6-7
Soil pH: 6-7
🌱 Fertilizer

The ideal time to fertilize Yellow giant hyssop is in early spring, as it comes out of dormancy and begins active growth. Fertilization supplies essential nutrients for healthy growth. Although Yellow giant hyssop has relatively low fertilizer needs, annual fertilization can improve its survival and promote better, longer-lasting flowers.

FAQ
Why should I put fertilizer on my Yellow giant hyssop?

Fertilization is important for the Yellow giant hyssop because it provides essential nutrients for the plant's growth above and below ground. While the Yellow giant hyssop has relatively low fertilization needs and can survive without it, annual fertilization can greatly benefit the plant by improving its overall health and promoting the growth of longer-lasting flowers. To ensure that your Yellow giant hyssop looks its best, it is recommended to maintain regular annual fertilization.

When should I fertilize my Yellow giant hyssop for best results?

The best time to fertilize a Yellow giant hyssop is in late winter to early spring. This is when the plant is waking up from its dormant phase and starting to grow actively. Fertilizing at this time helps the plant grow stronger and healthier during the season. Although it's generally best to fertilize in early spring, you can also fertilize in the fall if needed. However, it's not recommended to fertilize in the summer or winter.

When shouldn't I put fertilizer on my Yellow giant hyssop plant?

To ensure optimal growth of your Yellow giant hyssop, it is best to fertilize during late winter and early spring. This plant has minimal fertilization needs, so one feeding per year is sufficient. Avoid fertilizing in spring, summer, and fall to prevent overfertilization and its complications. However, if you missed fertilizing in spring, it is acceptable to feed the plant in the fall. Furthermore, refrain from fertilizing during the winter as the plant will be in a dormant phase and will not experience new growth.

What kind of fertilizer does my Yellow giant hyssop require?

For Yellow giant hyssop, any general-purpose fertilizer with a balanced amount of the three main plant nutrients will work well. However, some nutrient blends can be more beneficial. For better roots and flowers, gardeners often use fertilizers with higher levels of phosphorus. Granular or liquid fertilizers are both suitable if they provide sufficient nutrients. Additionally, you can improve the soil for your Yellow giant hyssop using organic methods like compost and manure. These materials are effective in creating a healthy growing medium.

How should I fertilize my Yellow giant hyssop?

To fertilize a Yellow giant hyssop, the most common method is to use granular or pellet fertilizer. It's important to apply the fertilizer when the plant is transitioning from its winter dormant phase to active growth. In early spring, wait for shoots to emerge from the soil before applying the fertilizer. Alternatively, some people prefer to use liquid fertilizer, in which case it should be diluted with water before application. Regardless of the type of fertilizer used, it's recommended to moisten the soil before, during, and after fertilization.

🪴 Pot & Repot
✂️ Pruning

The yellow giant hyssop is known for its tall spikes and yellow flowers. To encourage healthy growth, it's ideal to prune the plant from early to late spring. Key techniques include removing dead stems and trimming back one-third of the plant to promote bushier growth. This not only enhances air circulation and improves bloom production but also reduces the risk of disease, resulting in robust plants.

🌿 Propagating
🐛 Diseases & pets
☠️ Toxicity

Characteristics

Plant Type
Herb, Shrub
Life Cycle
Perennial
Genus
Agastache
Family
Lamiaceae
Hardiness Zone
4-9
Mature Height
1.22 m to 1.83 m
Mature Spread
91 cm
Leaf Color
Green
Leaf Type
Deciduous
Flower Color
Yellow
Flower Size
0.76 cm
Bloom Time
Mid summer, Late summer, Early fall
Planting Time
Spring, Summer
Harvest Time
Fall

Tags (6)

Common Names (2)

en Yellow giant-hyssop
en Catnip giant-hyssop