Perennial Tips
Anemone
(Japanese) Windflower These delicate plants come with specific requirements. They prefer a part shade environment with well-drained soil that does not dry out. Contrary to their common name, these plants need shelter from the wind and should be planted in a protected area. They can grow between 1 and 4 feet tall and wide, depending on the variety. The flowers are usually shades of pink or white and they bloom anywhere between August and October. Taller varieties might require staking but generally maintenance-free. No serious pest or diseases, but the blister beetle may be a nuisance, as they can strip the foliage from the plant.
Aralia
A unique plant with a tropical look. These part shade plants mix well with other shade plants such as hostas or coral bells. Prefers well-drained soil. Grown as a foliage plant that comes in different shades of yellow or green, it does produce tiny, white flowers in late summer. Grows about 3 feet tall and wide. No serious insect or disease problems and is deer resistant.
At Alwerdt's Gardens we: In spring, we cut the previous year’s growth to the ground.
Buddleia - Butterfly Bush
Their sizes range from dwarf (2-3 feet x 2-3 feet) to large (4-8 feet x 4-8 feet). Buddleias prefer their place in the yard where they can get full sun and have well-drained soil. Blooms available in many colors and some varieties are fragrant. Generally, a low maintenance plant that doesn't require much attention other than deadheading spent blooms encourages more blooms and will do so until frost. Available in many different colors and some varieties are fragrant. No serious disease or pest problems.
At Alwerdt's Gardens we: In Spring, we cut down all the previous years’ growth to new buds or lower, depending on size preference. This helps keep the plant neatly shaped and under control.
Coreopsis
Coreopsis is a tough perennial with many varieties to choose from. Likes full sun and well-drained soil. Depending on the variety, they can grow anywhere between 2-4 feet tall and wide. Coreopsis can be yellow, red, pink, or bicolored. Blooms all season long until frost. No serious insect or disease problems but can suffer from crown rot if the soil is too wet.
At Alwerdt's Gardens we: If the plant is looking messy, it can be cut back at any time during the summer to keep a neat appearance and encourage a fuller plant with more blooms.
Dianthus - Sweet William/Cheddar Pinks
Dianthus has many species and varieties to choose from. They come in many different colors and features making each cultivar unique. Size varies with each particular type but they typically stay between 1-3 feet tall. They bloom from late spring into early summer. This plant likes to be deadheaded, which can help insure its perennial lifespan. Prefers full sun with light afternoon shade in hotter climates. Soil should be well-drained as Dianthus can be susceptible to crown rot if left in wet soil. No serious insect or disease problems, may have to watch for snails and slugs.
At Alwerdt's Gardens we: Keep them deadheaded through the spring – optional. If not deadhead them when they are done blooming in summer. If your dianthus gets too big and splits, then cut the entire plant back to ground level.
Dicentra - Bleeding Heart
Old fashioned bleeding heart is a charming perennial that blooms in spring. It takes part to full shade, does not like hotter climates, and will go dormant if the temperatures get too high for it. Plant in well-drained soil, will not tolerate heavy, clay soil. These natives can get between 2-3 feet tall and wide and make a great addition to the woodland garden. No serious insect or disease problems.
At Alwerdt's Gardens we: Let them die back to the ground after they are done blooming and clean up the foliage.
Echinacea - Coneflower
Echinaceas have come a long way! Blooms are single or double and come in many different colors and distinct features. The coneflowers like full sun and well-drained soils. To keep a good perennial lifespan, make sure they are deadheaded as often as possible. It is often advised to keep your hybrid coneflowers from blooming the first year which forces the plant to grow a strong root system. Depending on the cultivar, they typically grow anywhere between 1-3 feet tall. No serious problems but may have to spray for Japanese beetles and watch for leaf spot.
At Alwerdt's Gardens we: Once they start blooming we deadhead them as often as possible. In spring, clean up any remaining foliage from the previous year.
Gaillardia - Blanket Flower
This plant has a showy bloom that attracts birds and butterflies and can last all season long. The blanket flower likes full sun and well-drained soils, will not tolerate heavy clay soil. These flowers grow between 1-2 feet tall, depending on the cultivar, and are available in solid colors and bi-colors. Deadheading is advised to keep the plant's attractive appearance as well as build a healthy root system. They look great in a perennial border or container. No serious insect problems, watch for powdery mildew and leaf spot.
At Alwerdt's Gardens we: Keep them deadheaded throughout the summer and cut them back in late fall. In spring, we clean up any remaining foliage.
Geranium - Cranesbill
This is an easy perennial to manage and a great addition to the garden. Geraniums like their light ranging from full sun to part shade and they prefer a well-drained soil. Depending on the specific species and cultivar, they can grow anywhere between 1-2 feet with a similar spread. The blooms come in different colors and some are scented. Groundcover species have beautiful fall foliage. No serious insect or disease problems.
At Alwerdt's Gardens we: It all depends on the species. Hybrid species are kept trimmed throughout the season to encourage more growth and keep a neat appearance, then cut back in late fall. Groundcover species are generally left alone and cleaned up the following spring.
Helianthus - Sunflower
These bright flowers will start blooming in late summer until fall. These short sunflowers are Missouri natives and they typically grow between 2-3 feet tall, with some hybrids reaching 4 feet. They attract birds and butterflies and make a great addition to the cut-flower garden or native garden. No serious insect or disease problems but you might have to stake taller varieties.
At Alwerdt's Gardens we: Maintain a neat appearance until bloom time. When the plant has finished blooming, cut it back to the ground in late fall/early winter.
Heliopsis - False Sunflower
These summer bloomers attract butterflies. They can grow anywhere between 3-6 feet tall with a 2-4 foot spread. They like full sun and prefer well-drained soil but are tolerant of poor soils. The false sunflower is a low maintenance plant but taller varieties may require staking. No serious insect and disease problems but watch for aphids.
Here at Alwerdt’s we: Keep them trimmed up to keep a neat appearance throughout the summer, deadhead to encourage more blooms, and cut them back in late fall. Any remaining foliage is cleaned up in spring.
Helleborus - Lenten Rose
Helleborus is a low-maintenance plant that is great for the woodland garden. Plant in part to full shade, too much sun exposure can burn the leaves. They bloom early, sometimes in late winter while there is still snow on the ground. These perennials have many hybrids now available with bold colors and patterns. They grow 1-1.5 feet tall and wide and like rich, but well-drained soil. No serious insect or disease problems.
Here at Alwerdt’s we: We really don’t do much with these. The flowers just seem to disappear and the foliage is evergreen. In early spring cut away any damaged foliage.
Hemerocallis - Daylily
A popular favorite for the garden, the daylily is a mid-summer bloomer or, depending on the cultivar, they can be repeat bloomers. These flowers have a variety of colors, shapes, and sizes ranging from 1-4 feet tall. Even when they are done, they have neat, grassy foliage that lasts until frost. They like the full sun and well-drained soil. They are an easy plant to grow, can be placed almost anywhere their size allows for, and have no serious insect or pest problems.
At Alwerdt’s we: Re-bloomers are kept neat and deadheaded until late summer. Daylily foliage can either be cut back to 2-3 inches in fall or wait until spring. In spring, cut back dead foliage to the ground.
Heuchera - Coral Bells
These plants can put some color in your shade garden. Ideally, they like a part shade environment, especially in hotter climates. They can take more sun with adequate moisture but the soil needs to stay well-drained. There are many new colors and patterns available. They grow between 1-3 feet tall and wide, depending on the variety. Flower spikes emerge in late spring and constant deadheading will keep them coming back. No serious insect or disease problems, watch leaves for rust or powdery mildew.
At Alwerdt’s we: Keep them clean and deadheaded until late fall. In spring, clean off any dead foliage.
Heucherella - Foamy Bells
This perennial is a cross between a heuchera (coral bells) and the tiarella (foam flower). Like a heuchera, this plant wants part shade, particularly in the afternoon. They grow between 7 and 12 inches tall making them perfect for the border or edging. Soil should be well-drained. In late spring they will start blooming short spikes of flowers in white or pink. No serious insect or disease problems.
At Alwerdts Gardens we: Keep them deadheaded and cleaned up until late fall. Since they are short plants, the foliage is left to die back to the ground and then cleaned up in spring.
Hibiscus
The perennial hibiscus has a bloom you just can’t miss. These plants are great for mass planting or as a specimen. Depending on the cultivar, they typically grow between 3-5 feet tall and wide. This hibiscus wants full sun and well-drained soil that does not dry out. They also like some protection from winds that can burn the leaves. They emerge later than other perennials so be patient. No serious problems but watch for Japanese beetles, whiteflies, and aphids that will destroy the foliage and flowers. Also susceptible to some rusts, canker, blight, and leaf spot.
At Alwerdt’s Gardens we: Once they have bloomed, we cut them back to about 4 or 5 inches tall in the fall. If they begin to dry and wither, they can be cut back sooner. New growth will sprout from the old growth. Depending on the winter, new foliage may not emerge until late May. New foliage will not emerge until the ground warms up.
Hosta - Plantain Lily
A very popular perennial for the shade garden. There are many varieties of different variegations of green, blue, and even yellow. They can have smooth, cupped, or rippled leaves. Hostas make a good groundcover and some cultivars can be planted as specimens. They range in sizes anywhere between 1-4 feet tall with the same spread. In mid-summer, they will put out stalks of white or purple flowers. Hostas can easily be divided and spread throughout your yard. Despite their low maintenance, they do attract slugs and snails that make the plant unattractive and eventually, weaken it. Other insects and disease problems vary by species and variety.
At Alwerdt’s Gardens we: Keep foliage clean of pests, remove spent blooms, and let them die back to the ground in late fall, clean up foliage in spring.
Iberis - Candytuft
A short perennial that only reaches about 6-12 inches tall with a 6-18 inch spread. It is ideal for borders and edging, rock gardens, and groundcover. The blooms appear in spring and the foliage is evergreen. Iberis likes full sun and a well-drained soil. No serious insect problems, but poorly drained soils can lead to crown rot.
At Alwerdt’s Gardens we: Keep foliage clean throughout the season, clean up any winter damage in spring.
Iris
Iris has many different species and varieties. They all like full sun and can tolerate light shade. Soil type depends on species, some want it well-drained (German, common flag), some tolerate wetter soil (Yellow Flag, Siberian) or standing water (Japanese water iris). Bloom times range from late spring to early summer. The flowers come in many shapes and colors. Problems come with different species, none serious with Siberian or water iris but iris borer, crown rot, and fungal leaf spot can affect German species.
At Alwerdt’s Gardens we: Keep spent flowers deadheaded, remove stems when done blooming, and clean dead foliage in spring. German irises benefit from division.
Kniphofia - Red Hot Poker
This unique perennial likes full sun and well-drained soils, will not tolerate heavy, wet soils. They grow about 3-4 feet tall with a 2-3 foot spread. They like an environment protected from wind and the crown should be well mulched to prevent rot in the winter months. An unusual late spring/early summer bloom, common types are red with the lower half maturing to yellow but new varieties are available with different bi-colors and solid colors. No serious insect or disease problems.
At Alwerdt’s Gardens we: Deadhead spent blooms, keep foliage clean, cut back to the ground in late fall.
Lavandula - English Lavender
This perennial is not just for the herb garden, it makes a lovely addition to the rock garden or cut flower garden. It likes full sun and well-drained soils. Grows 2-3 feet tall and 2-4 feet wide, depending on cultivar. Blooms purple flowers June through August, deadheading promotes flowering. No serious insect or disease problems, susceptible to root rot and leaf spot.
At Alwerdt’s Gardens we: Deadhead spent blooms. In spring cut back dead branches to emerging foliage.
Leucanthemum - Daisy
Daisies like the full sun and a well-drained soil. Depending on the variety, they can grow anywhere between 1-4 feet tall with the same spread. Blooms vary in size, shape, texture, and even color as they no longer are limited to yellow centers with white petals. They bloom from July to September, making them a popular choice for the cut-flower garden. No serious problems, generally susceptible to verticillium wilt, leaf spot, and stem rot, watch for aphids, leafminers, and mites.
At Alwerdt’s Gardens we: Deadhead spent blooms, keep dead foliage trimmed, cut back to the ground in late fall.
Liatris - Blazing star
Liatris wants full sun and medium-well drained soil. Very tolerant of heat and humidity. Grows 2-4 feet tall with a spread of 8-18 inches. Looks great in a mass planting, native, or prairie garden and will attract butterflies and birds. No serious insect or disease problems.
At Alwerdt’s Gardens we: Deadhead spent blooms, keep foliage trimmed and clean throughout the summer, cut back to the ground in late fall.
Lillium - Lily
There are many species of lilies, most common are Asiatic or Oriental. Both species like full sun and can take light shade. They like well-drained soil that does not dry out. Oriental lilies, depending on variety, grow about 3-4 feet tall with an 8-12 inch spread. Asiatic lilies tend to grow 2-3 feet tall with a 12-18 inch spread. They bloom in June-July, Asiatics tend to bloom first. They make an excellent cut flower and some oriental varieties are quite fragrant. Blooms come in a variety of shapes, sizes, colors, and patterns. Mulching around the base of the plants is necessary to prevent bulb rot and oriental types like protection from wind. No serious insect problems but diseases include botrytis and lily mosaic virus.
At Alwerdt’s Gardens we: Remove spent blooms, when leaves and stems turn yellow we cut stems in half until all of the plant has yellowed, then cut stems to the ground. Leave green foliage up as long as possible so that energy can go back into the bulb.
Monarda - Bee Balm
These unique blooms will attract butterflies and hummingbirds. Bee balm likes full sun to part shade and medium to wet soil. Depending on the variety, grows about 2-4 feet tall with a 2-3 foot spread. Blooms available in different colors, provide the perfect contrast to any perennial garden. Needs good air circulation, powdery mildew can occur if crowded. No serious insect problems may have to watch for rust, becomes more susceptible to diseases if the soil dries out.
At Alwerdt’s Gardens we: Deadhead spent blooms, keep foliage trimmed and clean, cut back in late fall, clean up any remaining foliage in spring.
Nepeta - Catmint
A good choice for rock gardens, perennial borders, or edging, this low grower stays around 8-12 inches tall, spreading 12-18 inches depending on the variety. Likes full sun to part shade, will bloom spikes of purple from May to September. Prefers to have a well-drained, drier soil and tolerates drought. They will attract butterflies and the occasional cat because the plant is so closely related to catnip.
At Alwerdt’s Gardens we: Keep foliage clean and trimmed throughout the season, cut back hard in late fall. Certain varieties, non-re-blooming types, benefit from a hard shearing after blooming, this keeps a neater appearance.
Oenothera - Evening Primrose
A low grower with fragrant blooms, this perennial stays short growing 8-12 inches tall, and spreads 12-18 inches. This plant likes full sun with dry to medium well-drained soil. Blooming from May to August, it is perfect for borders, rock gardens, and native gardens. A drought-tolerant plant that does well in poor soils. No serious insect or disease problems.
At Alwerdt’s Gardens we: Keep foliage clean during the summer, cut back in fall after it is done blooming.
Penstemon - Beardstongue
There are several species and varieties of penstemon but they all like full sun to part shade with a dry to average well-drained soil. Between the different types, they can grow anywhere between 2-5 feet tall and spread 1-2 feet. Blooms in late spring into summer, deadheading keeps the plant looking neat and encourages more blooms. Within the different types, the blooms and foliage are available in several colors. Good flowers for mass plantings, woodland areas, and cottage gardens. No serious insect or disease problems, leaf spot, and rot can occur.
At Alwerdt’s Gardens we: Deadhead spent blooms, cut back foliage in late fall, clean up in spring.
Perovskia - Russian Sage
Easy to grow, adaptable, tolerant of drought, poor soils, and air pollution. This perennial wants full sun and nothing less. They tend to grow between 3-5 feet tall and spread 2-4 feet. In mid-summer, it puts out tiny blue-purple flowers that last until late fall. Very aromatic. New varieties have really improved this plant with choices in leaf texture and size. No serious insect or disease problems, larger plants may flop and require staking.
At Alwerdt’s Gardens we: Keep foliage clean throughout the season, cut them back about halfway in fall leaving some foliage, then cut down almost to the ground in late winter or spring. We like to leave ours up for the winter effect.
Phlox - Garden Phlox
Performs best in full sun but can tolerate light shade. Garden phlox grows between 2-4 tall and spread 2-3 feet. These plants make great additions to any garden providing bursts of color from July to September. They need well-drained soil that does not dry out, watering is best done at the base of the plant, and good air circulation is needed to prevent powdery mildew. The flowers attract birds, hummingbirds, and butterflies. No serious insect or disease problems other than powdery mildew and new cultivars are available that are resistant.
At Alwerdt’s Gardens we: Deadhead spent blooms, keep foliage trimmed up, cut back plant in late fall leaving some foliage, cut back to the ground in spring.
Rudbeckia - Black-eyed Susan
This plant is very tolerant of heat, humidity, and drought and wants to be in full sun. Adapts in poor soils but prefers them well drained. They grow between 2-4 tall and wide, depending on the variety. The simple, yellow, daisy-like flowers bloom all summer long into fall, deadheading encourages more blooms. Excellent flowers for use in native gardens, cut-flower gardens, and mass plantings. No serious insect or disease problems.
At Alwerdt’s Gardens we: Deadhead spent blooms, cut them back in late fall, clean up remaining foliage in spring.
Salvia - Meadow Sage/Common Sage
There are a few different species of perennial salvia that come in many sizes and colors. They like full sun. Growing anywhere between 8 inches and 3 feet tall, they can be planted in containers, borders, edging, and great for a cottage garden. They prefer an average well-drained soil but can handle dry soils. Some of the advantages of salvia are its tolerance for drought and air pollution, slightly aromatic leaves, and they come in many shades of purples, pinks, and blues. No serious insect or disease problems, susceptible to leaf spot, rust, and powdery mildew with an occasional visit from aphids, whiteflies, and scale. Watch for resistant varieties.
At Alwerdt’s Gardens we: Deadhead when done flowering, keep foliage trimmed and clean, cut back in late fall or spring.
Sedum - Stonecrop
Sedum is available in many different species and varieties. They like full sun and a moist well-drained soil. They will tolerate some part shade, heat, drought, and poor soils which make them great for rock gardens. They give the garden texture throughout the summer with thick, rubbery foliage and then in early fall, they start blooming in clusters of color. Sizes vary with variety but most range between 10-36 inches tall with a similar spread. No serious insect or disease problems.
Here at Alwerdts Gardens we: Taller varieties can either be cut back in late fall or spring. Groundcover varieties can be left alone and cleaned up in spring.
Stachys
For byzantine species, commonly known as lamb’s ear, this perennial grows to about 8-18 inches tall with an at 12-18 spread at the least. During summer, flower stalks grow about 10-15 inches above the foliage and should be deadheaded to avoid seeding. Makes a great groundcover with interesting foliage that is silver and fuzzy. No serious insect problems but this species does not tolerate high humidity and can suffer from rot and leaf diseases. Can also be an aggressive grower.
Other species, commonly known as betony, grows 18-24 inches tall with a 12-18 inch spread. The foliage is green and puts up spikes of flowers in late spring to early summer. Good for borders and cottage gardens. No serious insect or disease problems with this species. Both species like full sun with average, well-drained soil. They are tolerant of poor soils and can be planted near black walnut trees.
At Alwerdts Gardens we: Deadhead when they are done blooming.
Tiarella - Foam Flower
A great addition to the shade garden, these little perennials are good for border plants, cottage gardens, a groundcover when planted in mass, or they are excellent for growing along river banks because they like a moist but well-drained soil. They bloom in spikes during late spring-early summer. Foliage varies by cultivar, they can be finely lobed or more rounded. They typically grow, depending on variety, between 8-12 inches tall with a 12-24 inch spread. No serious insect or disease problems.
At Alwerdts we: We don’t do much with these plants. They can be deadheaded if you have the energy. They are evergreen so you don’t have to cut back the foliage.
Tricyrtis - Toad Lily
This perennial is a great addition to the shade garden with its delicate, orchid-like blooms that won’t start showing until late summer into fall. Depending on variety, these blooms come in speckled shades of color from purple, pink, yellow and orange. Grows 18-24 inches in height and spread. Prefers a medium to wet, but well-drained soil. These plants are great for the woodland garden and should be planted where the tiny blooms can be seen and enjoyed. No serious insect or disease problems other than an occasional slug or snail.
Here at Alwerdts we: As a late summer/fall bloomer we cut them back to the ground in late fall or early spring.
Veronica - Speedwell
These perennials like full sun with a well-drained soil. They come in many different species and varieties making them a very versatile plant. Good for edging, massing, containers, and foundations. The blooms come in different colors ranging from shades of pink to purples and blues. Depending on the exact cultivar, they can grow anywhere between 4 and 24 inches tall with a similar spread. No serious insect or disease problems, root rot can occur in wet soils.
At Alwerdts we: Deadhead to promote continuous blooms. Cut flower stems to the ground in fall or spring.
