As gardeners, we want to give our world beauty and nourish the many insects that live around us. We're always looking for ornamental plants that will attract pollinators and look beautiful too. Hence, we dedicate this article to astilbe care: everything you need to know about it and how to grow it in your own shade garden.
Astilbe has feathery flowers and glossy green foliage that brightens up the flower garden. It's an excellent choice because it's virtually hassle-free and easy to grow astilbe. Since it is one of the best shade tolerant plants, you can plant astilbe in porch planters, under trees, and along penumbra lines to add interest to your space.
Not only do they attract bees, butterflies and hummingbirds also love their plumage, and this compact plant is resistant to deer and rabbits. Plus, they look great when planted with other ornamental plants like peonies, daylilies, and many varieties of irises.
The name astilbe means “without shine”, but due to the hybridization they are anything but boring these days. You can find a variety of colors within this species that are related to hydrangeas and bergenia. Now that you are as passionate about astilbe as we are, let's dig deeper into this beautiful ornament.
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Brief instructions for care
Proper astilbe care will bring you an abundance of beautiful flowers. Source: dan.kristiansen
|Common names||Astilbe, false goatee, false spirea|
|Scientific name||Astilbe spp.|
|Height & Spread||1-4 feet high, 6 inches to 2 feet wide|
|Bright||Shade to partial shade|
|floor||Well drained, rich in organic matter|
|water||Regular, even watering|
|Pests & Diseases||Asian garden beetle, black vine weevil, leaf spots, powdery mildew, wilt|
Everything about astilbe
Even all white astilbe is an option for your beds. Source: hartjeff12
The botanical name is Astilbe spp. and there are at least 16 astilbe varieties of this herbaceous perennial. Other common names are false goatee and false spirea. Hailing from East Asia and North America, they are known for their beautiful foliage. Gardeners especially love the contrasting deep purple to magenta colored flowers.
They have fern-like foliage with dark green leaves with thick stems and showy flowers that range from white to purple in color. Bridal veil Astilbe presents pure white flower tips with contrasting dark green foliage. Each spring has several tiny flowers that bloom from early summer through early fall. The ideal location for these ornamental plants is in the shady garden, where they are protected from hot weather – avoid planting in full sun.
You can grow different strains for a variety of brightly colored blooms all summer long. Or for a compact version that grows up to 2 feet tall is the Chinese astilbe (Astilbe chinensis). Since astilbes are a symbol of patience and devotion, they are often passed on to others as a declaration of love.
The best season to plant astilbe is spring, when the danger of frost has passed. If you share an existing astilbe, you can do so in the spring or fall, if the plant does not invest too much energy in growing it.
You should choose a location with partial to full shade. If you choose a location in full sun, your astilbe may not thrive if your surroundings are too hot. However, if you plant astilbe in full shade it may not get enough light to produce its brightly colored blooms, but it will have attractive foliage.
Another option is to grow astilbe in containers and garden beds, as long as it receives plenty of moisture and the soil drains well. The supply of nutrients throughout the season will also ensure they stay attractive. You can grow it from seeds, buy a plant from a local nursery, or share existing plants.
Each stem produces hundreds of tiny flowers. Source: KingsbraeGarden
Now that you have a better idea about this shade loving perennial, you may be wondering how and if you can grow the astilbe plant in your own shade garden. This section covers all of astilbe's growing needs to get you started.
Sun and temperature
In general, astilbe prefers light or partial shade, but tolerates full sun in northern zones as long as they get shade in the afternoon. The dark green foliage grows well in deep shade, but to get beautiful flowers they need at least 4-6 hours of sunlight a day.
The growth zones for this ornamental plant are USDA zones 3-8, depending on the variety. That being said, the ideal growth temperature is between 65 and 75 degrees Fahrenheit. They will not thrive in an environment that is exposed to extreme cold or heat. In the winter months, put a layer of mulch around the crown to protect it and the roots after you've pruned them for the season.
Water and moisture
Water your astilbe in the morning to give it plenty of moisture for the warmth of the day. You want to keep the soil moist, but not muddy – they don't like it when the soil gets dry and you will know this when the leaves are curled and drooping. Astilbe is not drought tolerant, but some varieties like the Chinese astilbe (Astilbe chinensis) have better drought tolerance than others.
Water deeply at least once a week (more often if it's particularly hot) and apply mulch to hold in moisture – dry soil will affect the plants. Water at the bottom of the plant to prevent water from splashing on the foliage, which could encourage fungal diseases. Keep watering until the soil freezes, then prepare the plant for winter.
Astilbe plants prefer well-drained soil that is rich in organic matter. The organic matter improves soil moisture and prevents it from drying out during the hot summer months. They do not thrive on heavy, loamy soils and prefer a slightly acidic pH of 6.0. If your soil has more loam in it, add extra organic content like peat moss, perlite, or coarse sand to improve drainage.
Blooming astilbe really adds a vibrant pop of color to the garden. Source: hartjeff12
Astilbe plants are heavy eaters and need plenty of nutrients throughout the growing season to stay healthy and produce beautiful flower heads. The best season for fertilizing is in spring with a balanced organic slow release fertilizer with an NPK ratio of 3-1-2 (nitrogen, phosphorus, potassium). Regularly enrich the garden soil with compost during the season and fertilize with a nitrogen-rich fertilizer in late summer.
If the flowers fade in the fall, you can leave them in place for the winter if you live in a warmer climate. For those experiencing a harsher winter, we recommend pruning your astilbe plants to help them survive the cold months. Cut all of the foliage within 3 inches of the top of the soil. After the first hard freeze, mulch around the plant to protect the roots. New leaves grow in spring.
There are three methods of propagating astilbe: starting from astilbe seeds, dividing existing plants or cuttings. Each has its advantages and disadvantages, with some being preferred over others.
Starting from seeds is a fun method, but it takes the longest since astilbe are relatively slow-growing plants. You can collect seeds from any current astilbe plants, but aged seeds have the highest germination rate. Alternatively, buy seeds from a local seed company and start them indoors at least 8 weeks before the last frost. You want your grafts big enough to tolerate the outside temperatures, usually in late spring.
Ripe astilbe plants benefit from division. So if you already have some in your yard, splitting is a good option. Split it up in either early spring or late fall when the plants are not putting a lot of energy into growing. Water the existing plant generously to make it easier to dig up the root ball. Once the root ball is exposed, divide the clumps into sections. Dig holes twice the size of each section to be planted and add compost to the soil. Water the departments well to avoid bumps.
The final method of propagation is by stem cuttings, but it is the least popular. This can be done at any time during the growing season, but choose stems that are free of flower buds. Cut the stem above a leaf knot, remove ⅓ of the lower leaves and place the stem in prepared soil or root in a container. Keep the cutting soil moist but not soaked and let the plant take root for at least 3 weeks.
Flower stalks extend over this plant before flowering. Source: sharon_k
When growing ornamental plants, there is always the possibility of growth problems, pests or diseases. This section discusses common problems and potential concerns with ideas for how to prevent and treat them.
Astilbe needs moist soil and plenty of nutrients to stay healthy. The most common growth problem is the soil drying out, causing the leaves to curl, turn brown, and then die. Water frequently in hot weather. Sometimes astilbe won't bloom, if they don't get enough light, transplant them to an area that gets more sun.
Another problem is not providing enough nutrients as astilbe is a powerful source of food and will not bloom unless it has enough reserves to draw from. Follow the fertilizing and watering recommendations as mentioned in the article above for the best results.
the Asian garden beetle is widespread in many plants and can be seen emerging in June, with the highest populations arriving in July. The beetle is reddish brown and lays its eggs in the soil at the base of the plant. When the larvae hatch, they feed on the astilbe plant. They are nocturnal. One way to get rid of this pest is to place light traps or hand-pluck them from your plants. Pyrethrins can help fight adult bugs, although they are not 100% effective.
Black vine weevil is another common pest that attacks astilbe. The larvae also feed on the roots of the astilbe, which makes them weak and eventually die. Adult black vine weevils are black and about ½ inch long with a pearly appearance on their rib cage and long antennae. Place insect pathogenic nematodes in your soil as the first line of defense to kill the larvae as they mature into larvae. Since the weevil doesn't fly, apply diatomaceous earth to the soil for extra protection and, in extreme cases, consider a biological insecticide that contains Beauveria bassiana, a species of fungus found naturally in the soil.
Common diseases are leaf spots, powdery mildew and wilt.
The mushroom Cercospora species causes leaf spots. Spores are carried by the wind or transmitted by splashing water (for example, when you water your astilbe and the water hits the leaves or splashes on the plant).
The infected leaf develops tiny purple or maroon spots that increase in size and eventually cause the leaf to fall off. It usually starts at the bottom of the plant and works upwards. To avoid leaf spots, remove any fallen leaves from around the plant and water at the base of the plant to avoid splashing. Sulfur and copper based fungicides prevent spores from breaking out, but are not treated once the plant is infected. Remove any affected leaves and / or use an organic fungicide.
Powdery mildew is also of fungal origin and, like leaf spots, can be prevented. Infested leaves appear to have been sprinkled with a white powder. If left untreated, the leaves turn yellow and die. Prevention is the best measure against fungal diseases, but you can use an organic fungicide to treat it. However, if it is severe, remove the affected plant to prevent the disease from spreading.
Fusarium wilt is a pathogen that damages the vascular system of the plant and for which there is no treatment. Your plant will show signs of not getting enough water, such as withered and brown leaves. However, the plant may only have signs on one side. The leaves eventually droop and dry up. Remove the plant, any roots, and any soil that the roots have been in contact with, as the pathogen can survive in the soil for a long time. Prevention is the best medicine, and some mycological additives prove to be helpful in preventing fusarium in the soil.
frequently asked Questions
Astilbe flowers stretch across the garden. Source: goforchris
Q: does astilbe need to be pruned in autumn?
A: Yes, in late fall, cut the stems back to 3 to 4 inches above the ground. Cover the roots with mulch to protect them during the winter months. However, do not mulch until the first freeze to prevent root rot and deter rodents from settling.
Q: When should I prune astilbe?
A: Unlike other flowering plants, astilbe with a dead head does not stimulate the growth of new flowers. Cut off old flowers as they die over the season, or leave them if you prefer the look of the dried flowers. Then cut back the whole plant in the fall to prepare for winter.
Q: How to keep astilbe blooming all summer long?
A: Provide plenty of nutrients for this heavy feeding plant. Fertilize a long-term fertilizer in spring or early summer, regularly enrich the soil with compost during the season and fertilize with a nitrogen-rich fertilizer in late summer. Also, don't put them in an area that gets full sun with no afternoon shade.
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