Weeding—does it ever end?

Weeding is one of those gardening tasks that some people find peaceful and enjoyable and others HATE!  Weeding is a component of gardening but it doesn’t have to consume all your gardening time.  Here are some strategies to help control weeds:

Use groundcover in your landscape beds to compete with weeds.  Most landscapes should have three layers—tree layer, shrub layer and groundcover.  When landscape designers, draw landscape plans, they tend to draw in large circles for the trees and smaller shrub circles, but often neglect to specify plants below the shrubs to cover the ground.  Few shrubs branch to the ground completely and therefore require a layer of plants below them to prevent weeds from growing in the bed.  The University of Delaware gets a lot of mileage from lilyturf (Liriope spicata) as a tough groundcover that out competes most weeds.  But, if you want more variety, you can try lamb’s ears (Stachys byzantina), bugleweed (Ajuga reptans), sweet woodruff (Galium odoratum), Allegheny pachysandra (Pachysandra procumbens)—a great native that takes a little while to establish but fills in thickly once it gets going, Christmas fern (Polystichum aristicoides) or barrenwort  (Epimedium sp.)—a great plant for dry shade.   Also consider planting perennials to fill in spaces rather than just shrubs.  Catmint (Nepeta  x faassenii ‘Walker’s Low’) is a great perennial that grows densely and out competes most weeds.  It is blooming now in Delaware gardens.  If you have a large space to fill, you might try mountain mint (Pycnanthemum muticum).  It is a vigorous grower and could become a problem in a small garden but its mid-summer flowers last until September in the form of silvery bracts.  It is also one of the best nectar sources for butterflies and bees so it is great to include in a pollinator garden.

Another weed control strategy is to cover the landscape bed with mulch.  Mulch will prevent light from reaching the soil, so few annual weeds are able to germinate.  You can generate your own mulch with composted yard waste and ground up leaves.  You can also buy leaf mulch or hardwood bark mulch.  Use mulch as a temporary feature, until your plants fill in or at the edges of beds to differentiate the landscape bed from the lawn.

Herbicides can be used carefully to control weeds as well.  Pre-emergent herbicides are used to control annual weeds before they emerge, by setting up an herbicide barrier in the soil.  It is a little late to apply a pre-emergent product this year, but something to consider for landscape beds next year.  Selective post-emergent herbicides can be used to control grass in landscape beds or broad-leaved weeds in lawns.  You can also use a glyphosate product (Roundup is one example) to spot spray weeds, but be careful because glyphosate kills most green plant tissue it touches.  It is easy to get spray drift and damage desirable plants.

Barrenwort (Epimedium sp.) in flower at the Delaware Center for Horticulture.

Barrenwort (Epimedium sp.) in flower at the Delaware Center for Horticulture.

Allegheny spurge (Pachysandra procumbens) on UD's campus.

Allegheny spurge (Pachysandra procumbens) on UD’s campus.

Finally, readjust your attitude about weeding.  Bring a cushion and a glass of iced tea outdoors with you.  Put on a good pair of gardening gloves.  Have a weed bucket nearby and spend a little time each weekend or evening relaxing in your garden and pulling up a few weeds.

Hydrangeas – Star of the Summer Garden

Summer?  Wait, we are just starting to enjoy spring weather.  But, now is the time to buy and plant trees, shrubs and perennials to enjoy this summer.  Do big blue and pink globes of hydrangea flowers remind you of your grandmother’s garden?  If so, come and get a dose of nostalgia or enjoy lots of trendy new hydrangeas .  Hydrangea is the featured plant of this year’s UDBG sale and is certainly a trendy plant in the industry.  This genus includes a wide range of plants from vines to large shrubs.

Bigleaf hydrangea  (Hydrangea macrophylla) is the old fashioned plant most of us remember from Grandma’s garden.  This species produces large balls of sterile flowers that are either pink in basic to neutral soils or blue in acidic soils.  The added fun of changing soil pH to change the flower color makes this plant unique.  There are also lacecap varieties in this group that have a ring of sterile flowers around a center of fertile flowers, looking like a lacecap (duh!).

Panicle hydrangea (Hydrangea paniculata) is another old time favorite. The flower head forms a large cone of sterile flowers with lots of fertile flowers in the interior.  Most are white, fading to pink but some new cultivars fade to pink more quickly and retain the pink color longer, even as dried flowers.  Panicle hydrangeas bloom on new wood, so they should be pruned in late winter to early spring, for the best blooms.

If you want a native hydrangea, look for smooth hydrangea (Hydrangea arborescens) or oakleaf hydrangea (Hydrangea quercifolia).  Smooth hydrangea is not super showy as the straight species, but several showy cultivars are available.  Oakleaf hydrangea is a popular coarse-textured plant with exfoliating bark and large globose flowers.  Oakleaf hydrangea flowers are white, fading to pink and often hang on the plant all winter, providing interest and structure to the winter garden.  Leaves in this species turn a beautiful burgundy color in the fall.

If vines are your thing, there is even a hydrangea vine (Hydrangea anomola spp. petiolaris) that adheres to rough surfaces such as masonry and tree bark.  This vine has numerous white flat-topped flower clusters ringed by white sterile flowers in the summer.  Use it on a wall next to a walkway where there isn’t room for a shrub or tree.

Hydrangea flowers are great for cutting and drying.  Plants tolerate a range of conditions from full sun to full shade depending on the species and cultivar.  Many new cultivars have been selected for smaller sized plants with different flower colors and shapes.  The UDBG Plant Sale was the last weekend in April but you can still access the catalog for a complete listing and description of lots of great hydrangeas as well as many other plants. Look at the online plant sale catalog by visiting this URL. (http://ag.udel.edu/udbg/events/documents/UDBGCat14_WEB.pdf).

Spigelia marilandica and Hydrangea quercifolia – Oakleaf hydrangea with a native perennial, Indian pink, in the University of Delaware Botanic Garden.

Spigelia marilandica and Hydrangea quercifolia – Oakleaf hydrangea with a native perennial, Indian pink, in the University of Delaware Botanic Garden.