August is the Time to Divide Perennials and Rebuild the Soil!

 Hello again,

Good gardening friend Paul Parent of the Paul Parent Garden Club sends out a great newsletter every week with pertinent gardening topics. I encourage you to go to his website to sign up for his newsletter. Paul can also be heard every Sunday morning from 6 AM to 10 AM at his website or at WBACH (104.7 FM) every Sunday morning from 6 AM to 9 AM.

We are halfway through the month of August now and it is now time to divide our perennials that have finished flowering and have outgrown their place in your garden. Dividing perennials is not just a way of making new plants with our overgrown plants, it is a way to revive them, and a time to remove the older portions that have become weak or died back and could draw potential insect and disease problems to your garden. Plants like irises, daylilies, hostas, peonies, and more are best divided while the ground is still warm and we have good growing weather and time for them to get established before winter arrives.

Here is an example why you need to divide your plants. If 3 years ago you planted one German iris rhizome in your garden in the fall, it will have flowered the next spring and as the flowering faded, the mother plant will have made 2 new side shoots for the following year. This would double the amount of flowers but the mother plant gave all her energy to the new plants and died. The following spring you now have two plants that will flower and when they fade these two plants will repeat the process, making two new plants each, giving you four plants for the next spring and again more flowers. The two mother plants also die so you now have four new healthy plants in the spring with three dead plants attached to them.

Irises have a major pest called an iris borer; it is attracted to your garden to feed on your dead rhizomes. This pest can also feed on the healthy tissue of your new plants preventing flowering in the spring. During August dig up the plants, remove the dead portions, clean the remaining healthy rhizomes--and now you have 4 healthy plants that should be insect-free. This is also the time to condition the soil and rebuild the soil quality so the new plants can thrive in your garden. Natural products like composts and manures will provide improved growing conditions for the new plants.

If you have had problems with the iris borer, it is also time to treat the soil with Bonide Garden Eight granules which will kill and borers that remain in your soil. Fertilize them with Flower Tone by Espoma and your plants will be ready to thrive for the next 3 years without problems. Also when you plant, cover the rhizome with one inch of soil or less. Space iris plants on 18 in centers so they have room to grow. If you’re adding mulch over the planting bed add less over the iris plantings because they want to stay close to the surface of the soil.

Plants like daylilies and hostas should also be separated to make new plants to share with friends and family. These plants grow in the shape of a fan; when you separate them. Try to create new plants that contain 3 to 5 fans of foliage for faster plant development and to keep from losing the flowering for a year or two because the new plants are too small. Condition the soil like the iris and keep well-watered until the fall arrives. Remove all faded or yellowing foliage and clean the new plants to keep them healthy. All three plants need to have half of the existing foliage removed when divided, as this will help establish the plants faster. Divide daylilies and hostas every 3 to 5 years, depending on their size. Space plants of daylilies every 2 feet and 3 feet between rows to allow room for future growth. Hostas will vary, depending on the variety--from 2 to 3 feet between plants. Mulch 2 inches deep helps protect plants during winters with little snow cover or with very cold weather.

Peonies grow from a swollen root or tuber underground and at this time they have pointed buds on them known as "eyes." These are next year’s foliage and flower buds. Remove all the foliage from the plant, dig up the entire plant, and clean the soil from the twisted looking roots. What you want to do is to cut them into pieces that contain 3 to 5 of these "eyes," so they will be strong enough to flower the following spring. Dust the cut you made with a general purpose garden dust or garden sulfur and allow to dry for an hour or two before planting. This will prevent rotting of the tuber when put back into the ground.

Condition the soil like the other perennials we have talked about and plant shallow, like the German iris. The pointed buds should have less than an inch of soil over them when placed in the ground or the plant will not flower when planted too deep--maybe that is why your plants are not flowering very well now in your garden. The tuber should be about the depth of your finger knuckle and when you dig into the soil you should be able to feel it easily. Space your new plants every 2 feet and 3 feet between rows to give them room to grow for the future. Peonies are divided every 5 years and should also be mulched lightly--about one inch thick--to protect the plant during the winter and help hold moisture in the soil during the hot days of summer.

Bleeding hearts can also be divided at this time, and--like the peony--the roots are covered with pointed buds for next year. Make you cuts with a sharp knife that has been dipped in a bit of bleach to sterilize it before cutting the plant and during each cut. Make sure each piece you cut has 3 to 5 buds so the plant can grow quickly and flower for you next spring. Condition the soil before planting and cover the new roots with 2 inches of soil and 1 to 2 inches of mulch them for winter protection and summer heat. Space plants 2 to 3 feet between plants as they will grow large when mature and divide them every 5 years. Fertilize in the spring with an organic flower food like Flower Tone by Espoma to help get the plants off to a quick start.

When you divide in the late summer to early fall, you help to create a better plant, as it can establish itself in a warm soil before the cold weather arrives. Spring-divided perennials start up slower and if the weather is warm and early like it was this year, the plants begin to grow before you have time to divide them--possibly hurting them. Look over your garden; any perennial that has finished flowering can be divided at this time of the year. Always condition the soil and keep the plant well watered until October. Use Bio Tone by Espoma to speed up the rooting process. It is well worth the small investment and most garden centers have it available right now. Bio Tone is also great for all your Fall plantings of shrubs, trees, bulbs and hardy fall flowers like mums and fall flowering asters.

This Saturday, August 25 we are holding a great class called Dividing, Relocating and Transplanting Perennials. Class time is 10 AM. We have openings still in Brunswick (442-8111) and Cumberland (829-5619)

Special Thanks to Paul Parent

Mike Skillin

Skillin's Greenhouses

August 21, 2012